Hi, Rusty!
Firstly , the dog is fine.......her anal gland is now cleaned out and she doesn't have to go back to the vet for two months!
Secondly, 13d......... this has me puzzled?
In France, once, change a strongly acidic element in brass (10)
I have "sousaphone" = brass (def)
But, as far as I know, the French for "sous" is not "once" as the clue would perhaps indicate?
"sous" means" under; beneath" in French?
I thought that "once" in French was "une fois"?
I'm wondering if the clue could mean "en "which is French for "in".......
and if 'change' means to invert it , giving "ne" at the end of "sousaphone"?
Or of course, Ne might be referring to neon?
because 'element' has to be accounted for , somehow?
a ph o - a ph of 0 is strongly acidic.
( We need Pigale to help out with the French here !)