Painting - Removing dryed on masking tape

I put masking tape on my outside metal window trim last fall to mask them off for painting adjacent pieces. Well I forgot to remove it around 4 windows so it's been there all winter for 1/2 year and now dryed/stuck on solid. I've tryed WD40, Goof Off, paint thinner, heat gun, finger nails - nothing seems to work at all. I can't use a scraper or razor blade as this will damage the paint that the metal trim came with from the factory. Any suggestions? Thank you.

Paint thinner coupled with lots of elbow grease should remove it. You might try covering the end of a putty knife with a rag to help scrape it off.

Are these painted windows or bare aluminum?

Try Goo-Gone, a citrus based remover, also try cigarette lighter fluid,usually actually naptha, as both of these items have been found to work sometimes.Try a plastic scraper versus a metal one but remember that plastic may break if you put too much pressure on it.When using any liquid or solvent let it soak into the tape for awhile and don't do this when the sun is directly shining on the surface as this will cause the solvent or some of the product ingredients to evaporate too fast to be effective.

IMO, I second the WD40. It's abundant, cheap and safe not to damage your paint. I've used it to remove residual pinstripe adhesive on my car without damaging the paint.

Try a different approach next time you use it. Spray a LIBERAL amount of WD40 and let the it soak for 10 minutes or more in order for it to get under the tape. Take an old rag and rub it down. You should notice the adhesive dissolve and stick to your rag. Repeat until its gone.

I've also had luck with the WD40.

If all fails try lacquer thinner. You will have to paint the metal as this stuff will remove the factory finish.