Homebrew PCBs

Here's a link to a US National Institutes of Health Report on
Carcinongens that addresses thiourea specifically as a potential
carcinogen:

<http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s175thor.pdf>

Notable in the report is this statement: "There is a small risk of
consumer exposure to thiourea in silver tarnish removers or in liquid
animal glues, which have been widely replaced by woodworking glues."

Ted