Nice empirical work. Bear in mind, however, sperm’s use as a conditioner.
I would also guess that washing in hot might play a part, at least with fresh sperm anything more than a couple degrees above body temp makes it curdle. wash in cold and you should be fine.
For some reason, that is horrendously gross in this context. Curdle.
BRB gonna make some cheese.
Heh, thinking of my old school friend Robert back in Texas. He used to jerk off into the cloth his kid sister washed her face with. So Carrie: If you’re reading this, now you know. 
Brain bleach please. :eek:
Unless you’re fucking a caulk gun, your towels should cum out fine.
You’re supposed to wipe it on her curtains, not the towels. Its less noticeable unless there’s a stiff breeze…
Semen contains mucus. When mucus dries out it can be somewhat crusty. I don’t know of any reason a towel would be any harder to get clean than a handkerchief, which wash up pretty well even after some fairly disgusting allergy bouts.
I dont think I have ever spermed on a towel.
I read the OP differently – that towels get stiffer once you remove the sperm. Therefor, to have the softest possible towels, one should never remove the sperm.