Most of the rubbers don't come with protective foil, but some blades do come with a thin and hard protective films to be used as rubber protectors, like this:
You can cut protectors from the transparent side of a plastic folder like this:
These protectors will fir perfectly to the rubbersq especially when both are clean.
Use them always.
After training clean the rubbers and fit the foils again.
Never use "adhesive" film, especially on such soft rubbers with "delicate" top sheet.