By the way--I know what you mean about that horrible pong from the rubber mask used by the dentists long ago, I had a lunchtime extraction and it made me so sick that I had to take the afternoon off from my job. It also gave me a very early reminder from the wartime, when as a little toddler, I wore a ' Mickey Mouse' style Gas Mask, made to fit us young 'uns, but it was frightening and sickly--lovely memory.