Rewrite Act Three; it will eliminate waste (8)
I believe the answer is:
catheter
'it will eliminate waste' is the definition.
The definition suggests a singular noun which matches the answer.
'rewrite act three' is the wordplay.
'rewrite' indicates an anagram.
'act'+'three'='actthree'
'actthree' with letters rearranged gives 'CATHETER'.
Can you help me to learn more?
(Other definitions for catheter that I've seen before include "Trace the strange tube used medically" , "Medical tube to remove waste from body - heart etc (anag)" , "Long, thin flexible tube for medical use" , "Thin flexible tube to withdraw fluids from the body" .)