Problem amalgamating tin and silver (4)
I believe the answer is:
snag
'problem' is the definition.
(snag can mean a problem or difficulty)
'tin and silver' is the wordplay.
'tin' becomes 'Sn' (Sn is the chemical symbol for tin).
'and' is a charade indicator (letters next to each other).
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'sn'+'ag'='SNAG'
'amalgamating' is the link.
This may not be correct. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for snag that I've seen before include "hurdle?" , "Problem or drawback" , "Rip or tear" , "Tear - catch" , "Glitch" .)