The rubber gasket on the rocker cover is stuck in the grooves .how the hell do you take it out?

is acetone safe for the metal ? I need to break up the rubber.I have tried heat - not worked. Previous owner must have glued it in.

I dont wanna scrape into the grooves .

I Spent hours polishing the top side up lol last thing I wanna do is buy another rocker cover. I think this gasket must have been on for 15 years +
hence it been caked.

Acetone won't affect the metal. Neither will Tar remover or MEK.
Nail polish remover is primarily acetone, and is also brilliant for insect bites.
As with any solvent, read the safety advice on the tin.