Removal methods include heating and rectification, absorption using a water absorbent, or {HEAD ~ a combination} of {TAIL ~ these methods} 
of
Removal methods include heating and rectification , absorption using a water absorbent , or { HEAD ~ a combination } of { TAIL ~ these methods }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL