I think I read here and elsewhere that pickle for bronze should be
made up using hydrogen peroxide instead of water to avoid the
dissolution of tin that leaves the surface of the piece pink from
a thin layer of copper. The strongest solution I can find in the UK
that can be delivered is 35% by volume (an EU Directive doesn't
allow anything stronger to be sent by road). Would this do the job?
Good grief do not even think about using 35% hydrogen peroxide. That
stuff is a fire or explosion waiting to happen, it is a strong
oxidizer.
Use standard pickle, the copper flash you sometimes get can be
removed by using a solution of 3% hydrogen peroxide and a small
amount of pickle = (8oz peroxide, 1 tbsp pickle).
James Binnion
James Binnion Metal Arts