Snape peered at Al, but he wasn't one to look a gift house-elf in the gob.
"Hmm, I've been using some of the number 6 coppers for a batch of Venerisolution, and coppers are always quick to tarnish. And I want to cut a new set of bamboo dippers: I was thinking of brewing something from that new Chinese scroll tomorrow - probably the Spring Pond Decoction - if I get the chance."