Tip jar upside down until cool to seal. Should keep for many months in the pantry.
Relish and Sauce that have vinegar in should keep well when you use the upside down method. Jam too. My sister swears by it and she makes litres and litres of jams, chutneys, sauces and relishes!
Yes I read recently that you can use your dishwasher to sterilise jars etc. I think you just have to have it on a really hot setting.
Metal in the microwave? Thought that was a no-no.