I have read that to get off spray paint “tagging” by gang “artists”
one technique is to heat the spray paint up with an electric heat gun
then shock stress the spray paint by touching it with solid dry ice
causing it to contract and break off at the layer between the 2 paints.

I have not tried this myself.

I have been amazed more than once in the past what a help dry ice is for certain uses.

Someone should do a youtube on “amazing things that you did not know dry ice could do”

I now own 2 UV-C disinfecting battery powered light “wands”
one by Brookstone,
another by the PureMobile division of Vivitar, Sakar International.

I wonder if Ultraviolet C light could degrade the spray paint after a certain time?
Mask off the original paint.

The electric arc of welding puts off intense UV light.