When I was brand new to jiu jitsu and i didn't even know what the guard was I rolled with an upper belt whose gi always stank. It happened 3 or 4 times on different occasions that I knew it wasn't a one off thing. His gi smelled liked after getting it super soaked in sweat/mat funk, he literally tossed it in the trunk of his car, let it marinate for a few days, then takes it back out and uses it again on the next training session! I don't know if he did that on my purpose but your post reminded me of him. He long ago quit that gym.