Sourcing and using the few chemicals needed to study lichens.

Lichenologists traditionally use commercial "thin bleach" as a test reagent ("C"). Unfortunately most modern commercial bleaches contained added caustic soda which makes them too alkaline for this purpose. BLS recommends checking this by making sure it doesn’t give the red positive reaction with the medulla of Parmelia saxatilis or P. sulcata.

It’s also been suggested that a mixture of 50:50 thick and thin bleach has better adhesion and penetration. Again you neeed to check the pH. I’ve been unable to find a source of neutral bleach recently and now neutralise the bleach by adding a few drops of dilute acid. Check for neutrality by putting a drop on litmus paper. When you reach the right point the bleach will be slightly yellow. If you go too far it will liberate chlorine, but this will stay in solution, or at worst, be trapped as foam. In any case do this out of doors and wear protective glasses.