How long is jam/marmalade safe to use?

[lyrabelacqua]

I've just eaten some marmalade which has been in the fridge for at least six months (previously opened). I thought it was safe if you scrape the manky bit off the top but then i looked at the jar and it says to use it within 3 weeks.
I always thought jam lasted much longer than this.

You'll probably be alright. I've done the same, in fact most people probably have. hardly a preserve though with 3 weeks to use by is it?

We have jars of jams etc that are years out of date and we haven't died yet! My test is to smell as well as look - I think smell is a much better test than looking.

I did scrape about an inch off the top, just in case. It tastes fine.