Little wheel keeps turning up in box (8)
I believe the answer is:
canister
'box' is the definition.
(I've seen this before)
'little wheel keeps turning up in' is the wordplay.
'little wheel' becomes 'caster' (small wheel attached to a large object. I am not sure about the 'little' bit.).
'keeps' means one lot of letters goes inside another (inserted letters are kept inside).
'turning up' says the letters should be written in reverse.
'in' reversed gives 'ni'.
'caster' enclosing 'ni' is 'CANISTER'.
Can you help me to learn more?
(Other definitions for canister that I've seen before include "Container for e.g. tea" , "Container for a film reel" , "Jar (of e.g. tea, sugar)" , "Metal container for storing dry foods" , "Container for storing dry food" .)