If you buy foods such as custard in longlife cartons, don't forget to open them up and use whats left in there, unless you squeeze the carton very well, there will be possibly another portion in there. This applies to other things as well such as tube whether its a spread or a toothpaste. Don't forget to empty tin and jars as well with a quick swill if adding to homemade food. For that last bit of jam, I add hot water and have a fruity jam hot drink!
I realised this is something I have been doing for years, that others don't think to do, so thought I'd share with you.