RT,

Thanks for the caution. I'll have to keep an eye on it. I'm not too worried about this brush, which is a Vulfix and seems to shed continuously. So far ClassicShaving.com hasn't responded to my request for a replacement...

What symptoms should I look for?

The warmer doesn't get my brush too hot to touch to my skin, while my tap water does burn me if I use straight hot water. So I'm thinking it probably isn't worse than my tap...

Josh