I don't wash my car that often, relying on the local hand car washes of late but often used the local petrol station wands. I have, though, occasionally washed by hand and and still have a fair amount of liquid which I think I bought from Costco in 98... It's got black mould in the top but seems ok, it's a 5 litre jobbie.. Will try and upload a picture but wonder how to dispose of it, together with the fresh coolant from my 2003 CRV, bought as a top up but didn't have to use much.