Has anybody got any tips for the long term storage of Duro / green stuff and for Magic Sculp?

I've had the two both stored togther in an airtight jar. What has happened is that parts of the hardener have gone ROCK HARD and has gone like glass. The Duro is starting to go the same way, but to a lesser extent. To be fair, I've had them for a few years

I will now store them separately. Or should I store the hardeners together instead?
Any suggestions welcome.

I would not store them together in the same container. I keep it in the original containers in a semi cool area (house temp - aprox 70ºF) in a drawer, and I've had stuff last for a couple of years without any issues. If you are just storing it, and not frequently using it then I'd suggest that you put each container in a zip lock bag and put them in your freezer. You can also 'revive' it some by microwaving the containers heating the putty, and then kneading. It wont be as nice when first fresh, but it does give it some life. Just don't nuke it too long (10-15 sec at a time) as it will get a little weird.

Thanks as always Anders. I will try the microwave trick. I've already separated then into two different containers and will store them out of sunlight.
To be honest though, when I think, the Magic Sculpt is about 6-7 years old..... so may be due a fresh batch anyway!

thank you again mate

all the best

Roy Hunt always recommended popping it in the microwave for a 10-15 seconds ,as Anders has also stated.
Worked for me.

Malc