In the filtration of fluid materials, the removal of particulate from the moving stream requires substantial pressure to maintain flow and substantial capacity for removing particulate. The filters of the invention are rugged, high wet strength materials having a basis weight, permeability and efficiency suitable to obtain substantial reduction in particulate loading from liquid streams without plugging or mechanical failure. In particular, the filters of the invention permit the removal of substantial proportions of particulate from non-aqueous streams including lubricant oils, hydraulic fluids and other contaminated streams.