Trouble with Calcium Oxide

[the guy]

Hello all.

I'm in a bit of a quandary with my tub of calcium oxide. I can only assume that at some point I have failed to seal the lid properly, or have dislodged it a bit when moving it. 
Whatever the cause, I discovered earlier today that the contents have swelled and lifted the lid to precarious new heights, and the resulting powdery tower looks worryingly delicate.

I have two options at this stage. I can either order a new, larger sealable tub to house it - though since the purity has obviously been compromised it will have limited uses - or I can attempt to dispose of it. 

Should I wish to dispose of it, what would be your suggestions on the best way to do this? It is quite a substantial amount and, of course, not a very pleasant chemical. I have dismissed my initial impulse of slowly dissolving it in an enormous container of water and waiting for it to convert to CaCO3 - not least because of the temperatures this might reach if I dissolve it too quickly, or the consequences should the container be upset - and would welcome any suggestions on how to go about this responsibly.

In the meantime, I will attempt the nerve-racking task of moving the container into a bucket without bespattering the rest of my belongings with quicklime...

[DrP]

I do not know why it did this - but I like to guess at things (to show how dumb I can be)...  Could it have gotten damp and then the dampness froze in the recent cold spells causing it to expand?  Maybe it 'set' like that with the weak forces involved with the damp particles. -  PURE speculation and probably wrong. lol. 

Does it crumble easily or is it set hard?

[John Cuthber]

I do know why it did this.

Quicklime is famous for expanding when it absorbs water.

One thing you could consider doing is converting it back to quicklime.

[the guy]

17 hours ago, John Cuthber said:

One thing you could consider doing is converting it back to quicklime.

I'm afraid I don't have the necessary temperatures at my disposal. I may just keep it as it is. The last couple of times I've used it were for preparing Ca(OH)₂ anyway, so for this purpose it will still suffice. And a modicum of CaCO₃ contamination shouldn't be a problem...