My DH goes running with this father weekly. They run near our house so FIL comes here first.
They run 10 or 15k usually and tend to come back very very sweaty! As soon as they get back DH will hop in the shower and put his running clothes straight in the wash.
FIL will sit on the sofa in his sweaty running gear and have a cup of tea, chat with me etc..
I've noticed that our sofa smells quite bad. I'm not saying it's all to do with this but surely it can't help.
I'm just about to get the sofa cushions dry cleaned. It's quite expensive. AIBU to ask FIL not to sit on sofa in sweaty running gear anymore, since it'll soon be nice and clean?