i wear two particular cycling jerseys on the trainer because i don't like them at all outside. when those two are used (once) i move on to cotton t-shirts. only my gloves don't get washed every ride. that is once a week. sweat towel every two days.
i have cardboard under the bike so just change it out from time to time. surprisingly i have not been dripping on the floor as much this year. maybe i've gotten soft.