Then I used this, which I like better as it doesn’t get you high or absorb directly through your skin, yikes:
De-Solv-It Contractors Solvent Citrus Scent Degreaser 12 oz Liquid
I used the De-Solv-It to remove similar glue from the hood of my BMW 2002, worked great on 52 year old gunk. I also used it to pull the faux wood from the interior of my 80. The 3M stuff works well too, but the fumes can be strong. Use a trim removal tool or very stiff plastic scraper to get the big chunks of dried-up weatherstrip off. Doesn’t need to be super perfect, just get most of it off the door.
When you’re ready to install the new ones, clean off the surfaces with a fast drying solvent of some type and then use a THIN layer of this stuff on BOTH the weatherstripping and the door frame, I used coffee sticks to spread it and did it in small 6” sections all the way around. Let it dry a little to get tacky before sticking it to the door. Be sure you are putting it in the right spot, once it sets up it’s a nightmare to take off.
3M™ Black Super Weatherstrip Adhesive
This is a great project, eliminating a big source of rattles on your 40. Not that there aren’t about 100 others…