Does anyone make chutneys or jams? I'm having a jar problem!

[WhatamessIgotinto]

I always try to reuse jars if I can rather than buy 'proper' new chutney jars etc. I wash them in the dishwasher then sterilise them in the oven and put the chutney in when both are hot to avoid cracking. Except it doesn't and I've just had another two jars crack.

What am I doing wrong oh mumsnet chutney/jam experts?

How hot is your oven? I do mine at 350 C

I reuse jars just as you describe and have never had one crack. The only thing I can think of is that they are too hot, ie are you putting the jam or chutney straight from taking them out of the oven and with the jam or chutney just off the boil?
I let them cool to warm before filling the jars

I warm jam jars in the oven at 50C, and also leave the jam for 10-15 minutes to cool a little before pouring it into the jars.

Oh that's where I'm going wrong - I thought you had to do it straight away when they were both really really hot so that the jar was sterile? I didn't realise you should leave them for a bit, thank you!