Dynamat is a rubber and aluminum sheet used for reducing the amount of road noise that enters your car while driving. Common areas to cover with Dynamat would be the doors, trunk, hood and chassis. However, problems arise when you no longer want the Dynamat in your car. Due to its sticky, tar-like substance, it is difficult, messy and time-consuming to remove. There are a couple accepted approaches to Dynamat removal: heat or cold. The heat method uses a heat gun or hairdryer, and the cold method uses dry ice. For either method, it is necessary to first remove any panels, carpeting, etc. to gain access to the Dynamat.
Start in the corner of the area from which you are removing the Dynamat. With a sweeping motion, heat up the Dynamat around the general area you are removing using a hairdryer or heat gun 3 to 4 inches away from the surface.
Move your heat source closer (2 to 3 inches from surface) to the starting point and heat the Dynamat until it begins to discolor and bubble a bit. Only use as much heat as necessary. Less heat equals less tarry residue.
Wearing gloves, slide a putty knife under the edge of the heated Dynamat and start scraping it off in the same direction you have your heat source pointed. You can attempt to yank off a section of the Dynamat with pliers at this point, but do it fast, like removing a bandage, or it will leave a lot of residue.
Buy dry ice at your local grocery store. The amount needed will depend on the size of the removal area, but an average car requires approximately 20 lbs.
Wearing gloves, prop the dry ice in the corner of the section you are starting from being sure it is in full contact with the Dynamat. Be sure the ice doesn't come into contact with any wires or cables.
Listen for a cracking sound, usually after two to three minutes for thin sections of Dynamat, and up to eight minutes for thicker sections. Once you hear the crackling, it's time to move the dry ice to the next section.
Use a hammer and/or putty knife to chisel away the frozen Dynamat. There is no need to be gentle here. Be aware of the body of your car as well as various wires/cables so that you don't accidentally damage them.
Vacuum up the chiseled off debris with a wet/dry vac. The dry ice will evaporate in six to eight hours.
