What kind of rubbery removable clear glue or adhesive is used to secure samples to magazines?

you can buy a more consumer-friendly version called removable glue dots that have about 1/2" circles of fugitive glue on a spool or sheet of wax paper, so they can be easily applied to whatever surface you'd like them on.

Sometimes you can find them at office supply stores, but I've found more exactly what I'm looking for by buying online, via Amazon or one of their associated merchants.