There is a layer of white on the fireproof door that can t be wiped off, and there are strips scrape

You said that the copper handle of the security door is actually not a copper handle, but a zinc alloy or aluminum alloy imitation gold treatment, white oxidation is indicating this, copper oxide is often green, people often talk about patina. Wipe it with a cloth dipped in white vinegar to remove it.

Don't deal with the big winter, wait for the summer to be warm.

Adhesive sealing, or using the same brush that brushes the hair balls of clothes is more effective.

I don't know if the door of your house is iron or wooden......Anyway, don't use gasoline, it will fall off the paint, you first try the dish soap with a cloth, wipe it a few times, or Bi Lizhu spray, and don't use pine water [don't use too much with this kind of water, don't use too hard, it may fall off the paint, use it with caution] The above two are safe to use.

The security door is generally about five dollars per floor, right? If the floor is relatively low, it is pressed every time.