This cupboard was the deepest shame of my kitchen.
Really. It was so bad. I was in a mood to face it though, so I flung open the doors and told the children to take everything out. After the cupboard was empty, I had the kids sort everything by round, square-or-rectangle, or "weird". Then, we put lids on the boxes we were keeping, recycled the boxes with no lids, decided what to donate, and put everything else back in to the cabinet.