Brownies regularly dropped anvil perhaps (4)
I believe the answer is:
bone
'anvil perhaps' is the definition.
(anvil is a kind of bone)
'brownies regularly' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternate letters of 'brownies' are 'BONE'.
'dropped' acts as a link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for bone that I've seen before include "Skeleton material" , "Part of skeleton" , "How dry" , "Carpal or tarsal, for example" , "Possibly hammer" .)