Tip for writer from Pound - flipping junk! (3,3)

'tip for writer' is the definition.
(tip of a pen, something which writes)

'pound flipping junk' is the wordplay.
'pound' becomes 'pen' (both can mean an animal enclosure).
'flipping' shows that the letters should be reversed in order.
'junk' becomes 'bin' (both can mean to throw away).
'bin' in reverse letter order is 'nib'.
'pen'+'nib'='PEN-NIB'

'from' is the link.