Originally Posted by Jel

That's a tough one tbh, if you approach him, he'll be embarrassed as fuck, assuming he has no idea. If you leave an anonymous note on his windscreen or smth like that, same thing but he'll be mortified as he won't know who put it there.

What I'd probably do, is stick a notice up to the effect of 'it has come to our attention that gym users are complaining about the lack of personal hygiene of other members, please make sure you aren't one of the offenders by making sure you shower before arriving as well as after your session, and wear a fresh change of clothing each visit', in various places if need be.

Doesn't embarrass any one person, and is done in a friendly kind of way, where not only will it hopefully solve the problem, it shows all gym users it's a 'clean' environment.

If that doesn't work, welp, you're more than likely gonna have to take a more direct line.