What a waiter may do? That's a lot of rubbish! (6,3)

'what a waiter may do? that's a lot' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'rubbish' is the wordplay.
I cannot really understand how this works, but
'rubbish' could be 'refuse' (both can mean waste material) and 'refuse' is located in the answer.
The remaining letters 'tip' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

'of' acts as a link.

Can you help me to learn more?