Lichen

[Oleanda]

Last year I successfully got rid of moss on a tarmac path with soda crystals, would it work on lichen on patio slabs, or is there something else I can use?

[Chipchopper]

'Armillatox' is one I've found to be effective, others may recommend 'Jeys fluid' other products like 'Path/patio clear' should be generally available, in fact, I saw some in the supermarket a short while ago.