Polyurathane Help

[Cops053]

Hopefully someone can provide and answer. The previous owner of my truck put in bed wood and polished stainless strips. I have removed all the crappy wood he used. My problem is, that he sprayed it all with polyurathane, wood and strips. Most of it has come off the stainless, but trying to figure out what to use to remove the rest of it from the strips without damaging them.....thanks in advance for any suggestions