I've cleaned a few sumps, the worst one was a Bridgeport clone, the column was half full of chips, steel, alloy, plastic and some oil too. I must have been the first person ever to look inside. It's worth having a look in Bridgeport sumps, tooling gets dropped in there and the oil keeps it in good condition. It's a good idea to wear gloves for this job, the chips are sharp and there are probably bugs that live in the oil. I wash out with kerosene or diesel fuel, throw in some cat litter, shovel and brush out the soggy mess, spray with oven cleaner and then wash out with hot water.