TL;DR
A heat mat collects the same sticky film that builds up on the tools it holds -- hairspray, serum, and dry shampoo, baked onto the surface by a hot barrel. Let the mat cool completely, then wash silicone with warm water and dish soap, or hand wash a fabric pouch in cool water. Scorch marks are usually permanent, and a mat that has hardened or cracked should be replaced.
What builds up on a heat mat
Styling products transfer from hair to tool to mat.
Hairspray is the main culprit. It is a polymer designed to hold, and when a hot plate or barrel touches a mat with hairspray residue on it, the polymer softens, spreads, and cures into a hard film.
Serums and oils leave a greasy layer that then catches hair and dust. Dry shampoo adds a fine powder that binds into the mix.
Over time the mat develops a tacky yellow-brown surface that feels sticky even when dry. That is polymerized product, not dirt, which is why wiping does not touch it.
The same film is what dulls the tools themselves, described in how to clean flat iron plates safely and how to clean a curling iron or wand.
How do you clean a heat resistant hair mat?
Let it cool completely, then wash silicone or coated mats in warm water with dish soap, using a soft brush or cloth to work the residue loose. Soak stubborn film for fifteen to twenty minutes rather than scrubbing hard. Rinse thoroughly and air dry flat before rolling it up.
Cooling comes first, always
Never clean a mat that has just held a hot tool. Silicone holds heat longer than it looks like it should, and a mat that feels warm at the edge can be considerably hotter in the middle where a barrel was sitting. Water on a hot mat can also spatter.
Give it at least fifteen to twenty minutes after the tool comes off, and longer if the mat has been rolled around a hot tool in a pouch. Unplug and cool the tool itself at the same time, which is the first rule for every heated styling item.
Silicone mats, which are most of them
Silicone is the easiest material in this category. It is nonporous, heat stable, and chemically tough.
Wash it in a sink of warm water with a good squirt of dish soap, working the surface with a soft brush or cloth. Degreasing dish soap does more than scrubbing here, because most of the residue is oil-based.
For a mat with baked-on film, let it soak in hot soapy water for fifteen to twenty minutes first. The soak softens the polymer and turns a hard job into an easy one. For anything left after that, a paste of baking soda and water scrubbed gently lifts residue without harming silicone.
A solution of one part white vinegar to three parts warm water helps with mineral spots. Use it on its own, never combined with any other cleaner, and rinse well.
Many silicone mats are dishwasher safe on the top rack, but check the instructions, since printed designs and bonded layers often do not survive it. Rinse thoroughly and air dry flat -- rolling a damp mat traps moisture between the layers.
Fabric and lined pouches
Heat-resistant pouches are usually a fabric outer with a heat-reflective or silicone-coated lining, and they need a gentler approach.
Check for a care label first. Turn the pouch inside out, shake out the hair and dust, and vacuum the seams if there is a lot.
Spot clean the lining with a cloth dampened with warm soapy water, working the residue loose gently. Do not scrub a coated lining hard, since the coating can lift. Hand wash the whole pouch in cool to warm water with a little gentle detergent if the label allows it, since machine washing can delaminate the lining.
Rinse thoroughly and air dry fully open, inside out first. Never put a heat-resistant pouch in a dryer -- the heat damages the lining, which is the part you paid for.
Can you get scorch marks out of a heat mat?
Usually not. A scorch mark is heat damage to the material itself rather than a deposit sitting on top, so cleaning will not remove it. A mat with scorch marks still works if the material is intact, but browning combined with hardening or cracking means it should be replaced.
What not to do
Do not use abrasive pads or scouring powder. They scratch silicone and destroy a coated lining.
Do not use bleach. It degrades silicone over time and damages fabric, and it should never be mixed with vinegar or any other cleaner -- that combination releases chlorine gas.
Do not use acetone or nail polish remover. They damage coatings and some plastics.
Do not machine dry or iron a pouch. Heat is what the mat is protecting against, not what it wants applied to it.
Do not store it rolled while damp. Trapped moisture causes mildew on fabric and a musty smell in silicone.
Do not put a fully hot tool into a closed pouch unless the manufacturer specifically says otherwise.
When to replace it
Replace a mat when the silicone has gone hard, brittle, or cracked, when a coated lining is peeling or flaking, when scorch damage has gone through the material, or when it stays sticky after a proper wash.
A degraded heat mat stops protecting the surface underneath, which is the entire point of owning one. A scorched counter or a melted laminate top is a much bigger problem than a new mat.
Check the underside too. Some mats have a grippy backing that hardens and stops gripping, which lets the whole thing slide with a hot tool on it.
The counter and the tools around it
A heat mat exists to protect a surface, so it is worth knowing what that surface is.
Quartz counters take no high heat, no bleach, and no abrasives. Laminate scorches and blisters. Natural stone can crack from thermal shock and is etched permanently by acidic cleaners. Painted or varnished wood will mark.
That is why the mat matters, and why a degraded one is worth replacing promptly.
Clean the tools themselves on the same schedule, and clear the dryer filter while you are at it -- see how to clean a hair dryer filter and vent. Keeping the whole styling kit on one routine is the approach in cleaning the personal items you use every day.
Source: U.S. Consumer Product Safety Commission guidance on the safe use of heated personal care appliances
FAQ
How do you get sticky residue off a silicone heat mat?
Soak it in hot water with a good squirt of degreasing dish soap for fifteen to twenty minutes, then work the surface with a soft brush or cloth. The soak softens polymerized hairspray so it lifts without scrubbing. A baking soda paste handles anything left, followed by a thorough rinse.
Can you put a hair tool mat in the dishwasher?
Many plain silicone mats are dishwasher safe on the top rack, but check the manufacturer instructions first. Mats with printed designs, bonded fabric layers, or a grippy backing often are not, and dishwasher heat can lift those layers. Fabric pouches must never go in.
Can you machine wash a heat resistant pouch?
Usually not. Machine agitation can delaminate the heat-reflective or silicone-coated lining that makes the pouch work. Turn it inside out, shake out the hair, spot clean the lining with warm soapy water, hand wash gently if the label allows, and air dry fully open.
Will scorch marks come off a heat mat?
Generally no. A scorch mark is damage to the material itself rather than a film on the surface, so no cleaner will remove it. The mat may still function if the material is intact, but browning together with hardening or cracking means it is time to replace it.
How often should you clean a hair tool mat?
Wipe it after each styling session while it is cool, and give it a proper wash every two to four weeks with regular use. Frequent hairspray users should wash more often, since the polymer film hardens quickly once heat has been applied to it.
Can you use vinegar on a silicone heat mat?
Yes, a solution of one part white vinegar to three parts warm water helps with mineral spots and some product film. Use it on its own and rinse thoroughly afterward. Never combine vinegar with bleach or any chlorinated cleaner, since the mixture releases chlorine gas.
Styling tools are quick to clean. The bathroom and bedroom around them take longer. If you would rather hand that off, get a quote or read more about house cleaning services.