Limewashing our fireplace wasn't the messiest project, but it did splatter a bit. So we put plastic down to protect the surrounding surafces.
Before adding limewash to the stone we soaked the stone with water from a squirt bottle and cleaned it.
To start we diluted the limewash with water to get the consistency we wanted. There is no rule for how to do it, but we found it was easier to work with thinner.
After we had the limewash mixed we began painting it on to the stone, starting at the top and working our way down.
We sprayed water directly onto the limewash and then began rubbing it off with the paintbrush or rag until we got to look we wanted.