In message , Chris Hogg writes
Agreed. We have four garden gates, a shed door and a sliding (galvanised, not aluminium) greenhouse door, with padlock, and I have been giving them all a squirt of 3 in 1 twice a year for 15 years, and all operate smoothly. I realise 3 in 1 is not perfect, particularly for an external padlock, but it works, stops things rusting (too much) and ensures smooth operation.