Removing Liquified Plastic Layer Residue From Notched Metal Surface

Question

I use old electric hob (as shown in the picture) for preparing my food, which takes a while to heat up and then takes even more time to cool down after use. Today I made a grave rookie mistake - as the hob was cooling down, I thought it would be a good idea to put my plastic cup of water on it, in order to warm it up. One minute later I recognized that the plastic began to liquify due to heat still being there, apparently...

Now, the second biggest mistake probably was my reaction, as I hurried to scrape the remains of hot plastic with a knife, which removed 99% of it, but a small visible layer of it still remains. It probably was not an issue, if the metal surface was smooth - but it's actually composed of many little notches, which makes it somewhat difficult to reach and clean them.

Therefore my question is - how do I remove that plastic layer lurking on top of the notched metal surface? Will heating itself be enough for it to slowly evaporate, or is there some other 'smart' way to react with this plastic?

Answer 1

I would use a heat gun or blowtorch. (If using a blowtorch on a gas stove, turn off the gas at the source, plus you might want to consider not doing this at all unless you know you can keep the hose from getting too hot and weakening.) And don't breathe the fumes--make sure the air is vented to the outside.

Sometimes heat will degrade a polymer enough so that a normally insoluble plastic can be wiped off with solvents like rubbing alcohol, acetone, or paint thinner. (Remember, they're all flammable.) If that's not the case, you can still burn it off with a blowtorch. That will leave residue that can be taken off with a metal scrubby and oven cleaner. The stove surface will be left gray and oxidized, and that can be cleaned with Barkeeper's Friend or other acid, but HCl would be my last choice, due to the risk of flash rust or pitting. Gloves needed for stronger acids.

I've used fire to clean some metal tools which had hardened polyester stuck to them. It turned gummy and could be scrubbed off with solvents. There are many plastics, and I can't say whether this will work. But burning should almost always work. I might burn it in stages to reduce the chance of hurting something inside your stove.

Answer 2

Remove the burner with the melted plastic. Take it to a hardware store for their inspection and advice.

Do not turn the burner on until the burnt plastic has been removed by someone (not you) who knows what they're doing and who has the place to do it in.

With added heat, the melted plastic will not evaporate. It will burn, carbonize, and treat the air you breathe in your apartment with aromatic hydrocarbons (known carcinogens). If you use industrial chemicals, you'll further contaminate the burner surface with those in addition to the melted plastic. Failing that, replace the burner.

You can ignore this and try cleaning hot plastic off a hot burner with more plastic or trashing the surface of the burner with materials and processes not recommended by the appliance manufacturer.

Answer 3

When the surface is hot, the plastic should be (as you said) liquefied. Provided it's below 450 degrees Fahrenheit, you should be able to "sop up" some / most of the plastic with a wadded paper towel. Make sure the paper towel is wadded up thickly to insulate you from the heat of the hob!

When the surface is cold, if it's possible (but too much work) to pick the plastic off of the hob, you may be able to remove a lot of it with a lint roller.