Such a mixture may be useless for many purposes. Make sure that any procedure necessary to prevent the cross-mixing of different solvents can and will be followed by all employees. Also consider reducing the number of different solvents used, if possible. Distill enough waste so that the recycled solvent can be tested in your facility. Solids and liquids that gel or polymerize can require significant amounts of labor to remove them from the still.
High solids can also coat and insulate the still's heating surfaces.
This causes the distillation to take more time and may cause hot spots and chemical decomposition. However, vacuum distillation can add significantly to the purchase price and operating costs of the still. Most still bottoms must be handled as hazardous waste. The disposal costs for pumpable liquid wastes will generally be less per pound than for solids or semi-solids. However, if the volume can be reduced sufficiently, the disposal of solids may be economically feasible.