You don’t see a lot of dust collector tricks in the woodworking magazines, but here’s my contribution. When your two-bag dust collector is too full, the usual solution is to remove the lower bag, let the chips dump all over the shop and then clean up the mess.
When I foolishly let my dust collector to get too full, I do something different. With the dust collector off, I punch down the top bag and then use my palm to compress the chips in the lower bag. This usually makes room for the chips that have piled up into the top bag.
And even if I don’t get every last chip into the lower bag, it greatly reduces the mess I have to clean up when I remove the lower bag.
— Christopher Schwarz