u-shaped rubber boot

Hello,

Your photos remind me of the 59-234 glazing for insulated glass. Review the information shown on our product page to confirm if this could work for your application. Thank you! 

Profile view of 59-234

What I would suggest is to use some denatured alcohol or acetone. Doctors use solvents like these to remove bandage tape. You can also try rubbing alcohol, although it's not as strong. Finally, you can always use a single-edge razor blade or a paint scrapper like our 75-046.

Normally, I would cut the vinyl glazing a little longer and just butt up the seam at the top of the window sash. If you want, you could use a little bit of caulk to close up the seam but that can create a bit of a mess if you need to replace the seal again down the line.