Thanks guys!
No secret to the cleaning - just plain lemon juice and a soft nylon brush to remove the deposits, followed by a dose of deller's to darken the tone. I only use lemon juice on coins that I know have a thin
patina, as when this is the case the metal below is almost always of excellent
quality and detail.
Yes, the
Diocletian did have some
silvering on it, but not as much as I thought it might. Unfortunately, since I [ahem] sort of forgot.. to protect the
silvering before applying the deller's it turned rather dark. The picture doesn't
help either. I may try to buff it back to a shine at a later date.
Richard