Casework and Finishing

Does anybody have a recommendation for cleaning and prepping a plate for refinishing?  We normally use naptha and have few problems.  I have a plate in the shop with terrible fish-eyes.  We have used Naptha... Lacquer thinner... and Acetone.  Nothing seems to work.  We are using the canned lacquer from the supply houses.  I realize we can use fish-eye killer mixed in with premixed lacquer but I don't have any premixed at this time.  Just hoping for a quick fix since we are using spray cans.  Thanks for your help!