The result of the viscosity test shows that, the used lube oil has
lost most of its viscosity due to oxidation or contamination. However,
treatment has improved its viscosity. It is clear that viscosity
at 40 C and 100 C, and flash point increase with increasing solvent
to oil ratio to reach maximum at ratio of 3:1 then they star
to decrease. The opposite trend is present in density, water content,
ash content, pour point, carbon residue (wt%), and total base
and acid number.