Active vs Passive Seasoning?

[the nub]

Originally Posted by RHNewfie

Thanks Tom, I didn't boil the water, just have a cup in there with beads. I am starting to question the seal a bit... but what do you expect for a 20ct from a Cuban flea market for 10 pesos!

I think that's your problem. Almost every one I've seen uses a thin ply top (1/8") with solid edging to make the top appear thicker. The outside of the top is varnished while the inside unfinished. This will always cause thin material to warp.