i use the https://www.amazon.com/Halo-Headbands-Skull-Cap-Black/dp/B00318BKGQ/ref=sr_1_1?ie=UTF8&qid=1509994986&sr=8-1&keywords=sweat+cap&dpID=41vogebE8QL&preST=_SX300_QL70_&dpSrc=srch and the 6mm fake leather foam pad, i sweat alot but i havent damage my headset yet, the cap helps capture alot of the sweats from your forehead so only your face sweat has any chance to get into hmd. combined with a fan blowing at your play space will help alot. Alot of people ask or wonder, if that skull cap will make you hotter, not really, the fabric on top is very breathable
I've got one of these that I use, and it works great! It also helps keep the HMD clean by keeping the oils or hair products from getting all over the straps.
Also, get yourself one of those sweat band skull cap things that footballers wear under their helmets. It really helped me.
Mine looks like this, although it was much when I bought mine. Halo Headbands Skull Cap Black https://www.amazon.com/dp/B00318BKGQ/ref=cm_sw_r_cp_apa_wfdizbKYKTH5Z
Get one of these and never get sweat in your eyes again
http://www.amazon.com/Halo-Headbands-Skull-Cap-Black/dp/B00318BKGQ/