Shisha Getting Started & Setup

Cleaning an HMD and Smokebox: Loosening Residue, Protecting the Surface

By Julian, Hookah expert

After the session, let your HMD cool down completely. Remove loose ash and tobacco residue, loosen hardened crusts with warm water and clean with a soft brush. Rinse thoroughly and dry everything. Cleaners and metal brushes have to suit the specific model.

12/10/2026 7 min read 1306 words

Summarize with: Claude ChatGPT

Schwarzes ONMO HMD neben einer weichen Bürste und einem hellen Tuch

In this article9 chapters

What has to come off the smokebox?
Which brush and which water?
Cleaning an HMD in six steps
Aluminium or stainless steel: what changes?
How do you tell whether the HMD is clean?
Undersides and surfaces in pictures
How often do you clean the smokebox?
What applies to electric bowls and the rest of the hookah?
Frequently asked questions

What has to come off the smokebox?

Recognising residue before you scrub
Area	What is left there	What you do
Charcoal area inside	Loose ash and charcoal dust	Remove cold residue and rinse off with water
Underside at the bowl	Tobacco and sticky molasses, later hardened crusts	Loosen with warm water, then brush off gently
Air openings and slots	Ash or tobacco residue	Check that the openings are clear and rinse out loosened residue
Metal surface	Dark discolouration without a layer that can be removed	Tell it apart from dirt; do not sand down to bare metal

HMD stands for Heat Management Device. In everyday hookah use, smokebox is a common name for the charcoal attachment. This article is about these metal parts. You control the heat during the session through the charcoal, the lid and the air paths; that is explained in HMD, Smokebox and chimney attachment.

Which brush and which water?

Start with warm water, a soft cloth and a soft brush without metal bristles. Only clean the HMD once no residual heat is left. An empty charcoal area does not automatically mean that the metal is already cold.

Steel wool, scouring pads and sharp tools are not general HMD care. Even a brass brush can leave marks. Only use stronger tools if the care instructions for your model expressly allow them.

Silver ONMO HMD next to a linen cloth on a light wooden surface

Cleaning an HMD in six steps

The sequence applies to charcoal-powered HMDs. You clean removable lids separately if they are meant for that. Do not take screws or firmly mounted handles apart on a hunch. The instructions for the specific attachment decide on cleaners and soaking.

Let it cool down completely
Remove the charcoal with the charcoal tongs. Let the bowl and the HMD cool down on a heat-resistant surface. Only touch the metal once it is cold, and do not hold the hot setup under water.
Take off loose residue
Lift the cold HMD off the bowl. Loosen loose pieces of tobacco and ash with a cloth or a soft brush. Check the underside; the photo shows an intact product view, not a dirt test.
Loosen crusts with water
Rinse with warm water. If hardened residue remains, soak it briefly, provided the care instructions allow it. Check in between whether it is coming loose. An overnight soak is not compulsory.
Brush off gently
Work on the softened areas with little pressure. If washing-up liquid is permitted, a little low-odour washing-up liquid is enough. If only water and a cloth are specified for your HMD, stick to that.
Rinse the openings out thoroughly
Rinse off loosened residue and any cleaning agents completely. Check the air openings all round. Do not poke them wider with a metal tool. The picture shows the clear underside of an ONMO Flat.
Dry and check
Dry the HMD with a clean cloth and let any remaining moisture evaporate. Look at the contact surface and the openings. Only put it back on the bowl or store it once it is completely dry.

Aluminium or stainless steel: what changes?

Check material and surface separately
Version	What matters	Care method
Aluminium	Do not wear away the contact bars and the surface	Soft brush, water; do not force a shine by scrubbing hard
Stainless steel	Even shiny surfaces get scratches	Begin gently; metal brush only with specific approval
Coated or coloured surface	Colour alone says nothing about approval for cleaning	No abrasives or dishwasher tablets on a hunch

Silver does not automatically mean stainless steel: the ONMO HMD Silver is an aluminium HMD. The ONMO Stainless Steel Classic belongs to the stainless steel line. So even two attachments of the same colour can need different care. In the slider you can see their real product views.

How do you tell whether the HMD is clean?

Look at the underside and the air openings: no loose crusts, sticky tobacco residue or cleaning agents should be left. Also check the inner surface on which the charcoal sits. An area that is darker in colour, on the other hand, does not have to disappear completely.

You do not simply keep using an HMD with a bent contact surface, cracks or a flaking surface. Sanding, burning out or hammering out dents are not part of normal cleaning. Have a damaged attachment checked.

Underside of the ONMO Stainless Steel Classic with openings all round and raised contact surfaces

Undersides and surfaces in pictures

Intact underside of a black ONMO HMD as a view for checking – dark lounge, HMD alone on a walnut table

Aluminium: look at the underside

The real ONMO view shows contact bars and openings. Here you check for hardened tobacco residue after cleaning.

Stainless Steel Classic: contact surfaces

This underside has raised contact surfaces. Clean the gaps between them carefully and check the openings all round.

ONMO Stainless Steel Flat from below with a flat contact surface and openings all round, on a dark background

Stainless Steel Flat: flat base

The Flat version has a different contact surface. Do not derive the care method from the similar outer shape alone.

Silver ONMO aluminium HMD with an open charcoal area and side slots – slate plinth, warm side light

Silver aluminium: side slots

The silver base model is made of aluminium. The air slots and the inner surface are part of the check after rinsing.

ONMO Stainless Steel Classic from the side with a shiny surface and side slots, on a dark background

Stainless steel: shiny outer surface

Here too, vigorous scrubbing can leave scratches. After cleaning, the surface does not have to look freshly polished.

How often do you clean the smokebox?

Check your HMD after every session, as soon as it is cold. Remove ash and fresh residue straight away, before it sets over several bowls. How much work is needed depends on the actual condition. A clean surface does not need vigorous scrubbing just because of a fixed weekly schedule.

Store the cleaned attachment dry and protected from knocks. Do not leave it lying in water permanently. The next time you build a bowl, the point is again the right build height and the contact with the HMD; you will find the guide under Building a hookah bowl.

What applies to electric bowls and the rest of the hookah?

An E-HMD with a battery, contacts or heating electronics is not a metal attachment for a water bath. There, only clean the parts expressly intended for it, in the intended way. The differences are explained in Hookah without charcoal.

You care for the glass base, stem, hose and bowl separately; Cleaning a hookah guides you through the whole setup. Cleaners for the glass base are not an automatic approval for a coloured smokebox.

Frequently asked questions

Can I put my HMD in the dishwasher?

Clean it by hand unless the instructions for your model give express approval. Aluminium and coloured surfaces in particular can be damaged by dishwasher tablets or aggressive cleaning. Stainless steel alone is not approval for the whole component.

Is a dark spot on the HMD automatically damage?

No. Heat and contact with tobacco can discolour the surface. What matters is whether residue is sitting on it or whether the surface is damaged. You remove loose crusts; you do not sand away a mere difference in colour. If there are cracks or flaking areas, have the attachment checked.

Can I use vinegar, citric acid or baking powder?

Do not use such household remedies as a standard cleaner for every HMD. Material, surface and coating differ. Start with warm water and a soft brush. An additional cleaner needs approval for the specific model; do not mix products together.

What do I do if the lid will not come off?

Let everything cool down completely. Then move the lid carefully, without force. If there is residue, a short warm water bath can help if your model is intended for it. Do not pry with a blade, and do not heat the attachment to loosen it.

Why does tobacco residue stick to the underside of the HMD after the session?

Depending on the setup, the underside sits close to the tobacco or touches it. Molasses and leaf pieces can stick there and become hard with the heat. Clean the contact surface when cold. For the next bowl, check the build height and the intended distance instead of sanding down the HMD base.