This is a very simple demonstration that illustrates some interesting chemistry.
A bath is made up of three different dyes: a direct dye, and acid dye and a disperse dye. These interact differently with the chemical groups on different types of fibres. It is an interesting introduction to hydrogen bonding at Higher and a fun activity at any time.
As a result, dipping different cloths into the same bath can result in them being dyed different colours.
Magic dye risk assessment