Shred waste in safe place to start with (4)
I believe the answer is:
wisp
'shred' is the definition.
(I've seen this before)
'waste in safe place to start with' is the wordplay.
'to start with' says to take the initial letters.
The first letters of 'waste in safe place' is 'WISP'.
(Other definitions for wisp that I've seen before include "(Smoke) thin plume" , "Small tuft of hair" , "Shred" , "Light streak of smoke or stray hair" , "Small thin line of cloud or smoke" .)