Note birds covered by beer: they go into the pot (3,6)
I believe the answer is:
tea leaves
'into the pot' is the definition.
I can't tell whether this definition defines the answer.
'note birds covered by beer they' is the wordplay.
'note' becomes 'te' (musical note).
'birds' becomes 'aves' (I've seen this in another clue).
'covered by' means one lot of letters go next to another (on top of in a down clue).
'beer they' becomes 'ale' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'aves' after 'ale' is 'aleaves'.
'te'+'aleaves'='TEA-LEAVES'
'go' acts as a link.
Can you help me to learn more?
(Other definitions for tea leaves that I've seen before include "Thieves" , "Source of drink" , "Magpies" , "found among the dregs" .)