I know this has been covered a few times but thought I would through out something that has worked well for me.

I am trying to get off 20 yr old paper and had been making rather slow and difficult progress with Goo Gone and Simple Green.

Today I tried "Goof Off Citris Gel". Worked fabulously.

It goes on heavy (its a gel), then cover it with Saran Warp.

After doing this I came back 3 hours later and the old paper and glue came right off.

http://www.homedepot.com/p/Goof-Off-...86?N=5yc1vZ4jx


They do make a clear industrial clear liquid (in a can) that harms the plexi (dont ask).

The citus gel does not though.

Larry S.