another anecdote: some A level students were doing something which involved copious quantities of very strong alkali. they were all wearing gloves and goggles as a precaution. but one guy got an itch on his nose. he scratched it, and then noticed the itch was getting worse. so he scratched it again. what had happened was he had a tiny amount of alkali on his fingerwhen he scratched his nose and it started to burn him. he was taken to hospital where he had to have a small skin graft on his nose because he burning was so bad.