Please Help, Stuck LeCrueset Canister Crocks, Might Have to Break One

They are sitting in Dawn water right now. I have also tried squirting WD-40 down in them but I can't get them to budge or even move the tiniest bit. The are quite heavy and awkward to handle. The largest one that you can see is 10" high. I've never had anything so hopelessly stuck as these are. I can't even get the blade of a thin knife down inside. Does anyone have any ideas? TY!

 

I would dry them off. Then fill the small one with ice. I'd let it sit for 30 minutes or so. I would pic it up by the rim of the small one and then tap the edge of the large one (I would use a rubber mallet) When tapping, I would tap one spot, then the spot directly across, Then shift 90 degrees and tap there, then directly across, then 90 degrees etc. Make sense?

 

Thank You!!! I tried the cold water thing because I saw it on the internet as a way to break apart 2 glass tumblers. Didn't think it would work. They said to put ice water in the top one and then immerse the bottom one in hot/warm water. With my husband pulling up and me holding down, it finally worked and they separated. Your solution with the rubber mallet would probably have been better than brute strength, a lot easier on the DH, LOL! I am so pleased these are finally apart. They are canisters and I have the lids for them, they are new condition and I didn't want to break one.