Or just use some yellow or red. Something nice and soft. Unlike when waxing for skiing, don't be shy about the amount of wax used for covering the base of the ski. Cover the entire base with an ample coating and DON'T scrape it off. This thick layer of wax will protect the ski throughout the summer and keep it from getting oxidized.
Oxidation occurs when the base is left unprotected and starts to turn white.
Those who took their last ski two months ago and didn't put a protective layer of wax on their skis may see this happening already. It makes it harder for wax to adhere to the bottom of the ski. Skis are expensive. It makes sense to protect them. Finally, there are several rules for storing the ski.