In 1968 my then wife had a 1963 Mini with an MG1100 engine. It needed some minor bodywork, as they do, and I re-painted the new parts with Almond Green cellulose.
Fast forward to today when I went to paint the underside of the 1865 850 I'm currently restoring. It is Almond Green. After priming it this morning, I then needed to get the Almond Green cellulose paint out and came across the remainder of the Almond Green I bought in 1968. There was almost 1 litre of partly thinned paint, so I decided to try it. I thinned it a bit more and sprayed it. Wow, that old paint went on superbly. The old Cellulose was much better than this modern stuff and it dries so much quicker.
Who would have believed partly mixed paint can last almost 1/2 a century and still go on beautifully?