[chickpeacurry]

Looking under my sink for washing up liquid and found some old feeders is there a best before date or do they last indefinitely. 

[JayG]

They will definitely work better than washing up liquid whatever condition they are in! 

Assuming they are liquid concentrates, I'd check for obvious signs of degradation, particularly excess sediment - some contain seaweed extract which may not be as stable as purely inorganic solutions, but TBH I'd use them anyway. 

[bravemurphy]

They had a load of Tomorite cheap in wilkos a few years ago so I phoned the help number on the bottle and asked if there was a best before date and the lady told me as long as it does not get too hot or frosted then it would be ok, so I bought enough for a few years and it is still working ok.