Cleaning Blue Case After Normal Use

Hey everyone! I think its been about a year since I got my FP5 from murena, with the blue case. I noticed early on that from normal use it got stained and a bit dirty. Keep in mind I live in a really hot country (summers reach around 45°C) so sweating is unavoidable, especially if Im helping a relative with their garden/general house maintenance, or similar activities that equal unclean hands + sweat.

Ive tried wiping it with a wet wipe, but the stains remain.

Any ideas for what I can use to clean it without damaging the material? Im thinking of trying rubbing alcohol but Id like some advice before I try anything new, to avoid damaging it since its a non-standard recycled material.

Id also like to keep this colour of case since I really like the blue :)