Old plaster.

[MORELLO]

Any ideas what was used to make plaster 100 years ago? I took the plaster off a stud wall yesterday, and despite goggles & mask for most of the time - very dusty job - my skin and eyes still don't feel right?

[buildersmate]

Probably got lime in it - which is quite alkaline.

[WILLIAMSON_P]

horse hair was also used as part of the mixture. their tails i think.