Aerospace Protectant 303 could also be an option as it is often used to clean and protect edrum rubber cymbals.

In Europe this product is difficult to find and we tend to use a product called Protectolan for that purpose: https://www.drum-tec.fr/protectolan-...tection-100-ml
I do use that one or my rubber cymbals and if I still had drivers with rubber surrounds I would be tempted to try it on them.

There is also this one called CYMPROTECT: https://www.r-drums.com/english/shop/cymprotect/