Alum salt 1 kg

Treat and fix stained surfaces where colors may bleed through via capillary action (especially old lime paints) with a layer of alum salt

Prepare 100 g of alum salt with 1 liter of hot water.

Mix for 5 minutes.

Apply with a whitewash brush in one to two coats.

Can be recoated after 24 hours; brush off any dry salt residue.

A mineral mass forms upon cooling.

Also used in the formulation of lime plasters and whitewashes.