This test from Inland Vacuum Industries will immediately tell you if your pump fluid needs to be changed. The procedure is easy to follow and doesn't cause any mess at all. Each kit contains five test vials.
WARNING: Test solution contains toluene, so used test vials should be disposed of like other waste solvents. Leave the vials capped since the atmosphere affects the indicators color.
Does not indicate the presence of Lewis Acids, i.e. AICI3, BCI3 ${pricetable pn='ATK1'/}