Most commonly, the mixture of incompatible greases will become soft and runny, but occasionally they will harden instead. In either case, grease incompatibility will cause the resulting mix to be out of parameter. The only solution is to flush and reapply. These powders act as friction modifiers for the grease. Because the grease is thick, the solid particles can be suspended and uniformly distributed throughout the grease.
Greases possess many of the same qualities that are common to liquid lubricants.
The additives used in the oil portion of the grease improve the natural characteristics and provide new, desirable characteristics. Too much of either characteristic is undesirable. The ability to produce a long strand of grease when stretched between thumb and forefinger does not necessarily mean the product is a quality grease. Very tacky grease can offer too much resistance to movement because of its extreme stickiness. This can actually be very detrimental.