Every time I open or close the allotment gates I carry a spray bottle of bleach cleaner in my bike basket which I spray on the lock and where I touch the gate. I was wiping my hands on my loose shirt, then found I had bleached some of the colour out of it. Changed the mix in the bottle to a weak industrial alcohol mix and it stopped the nagging from home. Ran out of alcohol the other day so made up a mix of cheap aftershave which was mostly alcohol anyway. Works a treat but leaves me smelling like an over fifty divorcee on a speed dating walk.