Corroded a metal until tip of electrode's absorbed (3,4)

'corroded' is the definition.
Although both the answer and definition are past participle verbs, I can't understand how they can define each other.

'a metal until tip of electrode's absorbed' is the wordplay.
'metal' becomes 'tin' (tin is a kind of metal).
'until' becomes 'to' (I've seen this in other clues).
'tip of' suggests taking the first letters.
'absorbed' indicates putting letters inside.
The initial letter of 'electrodes' is 'e'.
'tin'+'to'='tinto'
'tinto' enclosing 'e' is 'teinto'.
'a'+'teinto'='ATE INTO'

Can you help me to learn more?