I'm usually theme-blind too - after I've solved a clue I forget the answer - but I saw this one rather later. It's a bit niche, though, and you have to be quite old! It was pestle/vessel that jogged the memory.
Snap, redpete. I must confess that I haven't seen the1955 film (I'm not a fan of the star), but I've come across the clip before. There's a link posted on fifteensquared if you want to check it out.
redpete, I was out until late last night, so skipped Enigmatist and wasn't even aware of it...I'm in Eastern US and usually do the Guardian dailies in early evening just after 0:00 UTC.
Won't even try it unless tonight's Prize proves unusually easy.