Season 9, Episode 7: "The Slicer"

...a common ingredient in metal cleaners.

Well, that's weird.

What are you doing?

Well, I'm, cleaning my slicer.

That's my hand towel.

I use that on my face, neck and chest.

That's where the hives are coming from. It's not Dr. Sitarides.

It was Dr. Van Nostrand.