Cutting foam double sided sticky tape is always messy on your scissors, at least for me. Pretty soon they start to stick to pretty much everything you try to cut. Even the thin tapes will make your scissors sticky over time.
I have various sized straight bladed scissors and I tend to work through them until they are all sticky to some degree, they go in an old ice cream container. I then get out the eucalyptus oil or goo off or whatever you use to take glue labels off etc. With eucalyptus soaked cotton wool balls I clean up all the gunk off my scissor blades, give them a wash in hot soapy water with a cloth and rinse then dry.
While you have your scissors out and clean grab some very fine sand paper and cut thin strips from right down the bottom of the X to the tip 4 or 5 times. Wipe down with a cloth to get any grit off and set aside. Do this to all your scissors. Clean up your kitchen, sewing or even garden scissors this way.
I don’t use my decal or shape edged scissors with sticky tape but I do cut the fine sand paper to sharpen them up.
I also use the sand paper to sharpen my guillotine blade. I then dust it off and oil the hinge on the handle at least twice a year.
I hear a lot of people use aluminium foil for sharpening but I didn’t find that helped, by all means give it a try if you wish.