Barely 70 C is nowhere near proper sauna temperature, 90 - 100 C is more like it (and I'm only half finnish). Pouring sweat on the hot rocks seems like a bad idea, I suspect it would not smell particularly nice... clean water or beer is much better. And of course you go nude in a sauna, anything else is unhygienic! Spread a towel to sit on, though, and shower before dipping in the pool.