Whenever two greases with different thickener systems are mixed in service, there is a possibility of incompatibility resulting in poorer performance. It is always preferable and advisable to clean the old grease completely from the bearing prior to using a new grease. In cases where this is impossible or impractical, this chart can be used as a guide. The chart lists various common grease thickeners and their relative  compatibilities. Greases rated compatible are expected to be interchangeable in applications without any effect on lubrication properties. Greases that are rated incompatible should not be mixed in any application; the old grease needs to be cleaned from the bearing completely. Those rated borderline will usually be compatible, but should be carefully monitored in the period when the old grease is being replaced by Thixo Tak2.