Tar covered stainless dishwasher

I use a blunt chisel and remove all of it that I can. My yard downgrades it otherwise.
A heavy hammer blow from the inside of the panel loosens it right up making removal easier.
If your yard accepts the panels with the dampening sheet attached then leave them on.

I have done a few of these, not a fun job! Technique and method I found was to let the sun soften it up for a couple of hours. Then outside in front of a fan (maximum ventilation), We use a heat gun with a scrapper attachment. We also will cut these stainless steel sheets into smaller sizes, making easier to handle before cleaning. I have never cleaned them 100%, just get the thick stuff off! Then sell with the rest of your stainless.