Assassin Snail Eggs are a pain in the bum to remove

I pulled a driftwood from my tank that had 10 assassin snails in it. Well they love laying eggs on it, so the whole driftwood was practically covered in empty egg shells.

I let the driftwood dry off thinking the egg shells would come off without a hitch, but I think they are harder to brush off once they get dried or rehydrated. I already spent 2 hours brushing the driftwood like a crazy mad person with my toothbrush and there are still some egg shells left