As long as you squeeze all the air out of the bag and seal it you will be ok, old resin I just dump in the bin.
PS. What's happened to the window cleaning academy
Thanks for the advice guy's

first time changing my resin. lasted since January so no complaints, the 11'' di vessel I have, was a sod to unscrew, but got it in the end, shook out all the old resin and a big sponge piece popped out :

now did it pop out from the bottom or the top??
The academy is up and
running limping at the moment

but Joe and his boys are working on it still.