Lime staining is free lime, generally from mortar, which has been washed from the mortar joints on to the face of the brick. Lime staining can occur with any brick as it generally comes from the mortar. This can be prevented by protective details in the design such overhangs, drips, copings and sills that stop copious amounts of water reaching the face of the brickwork. The remedy for lime staining is to clean it off quickly.