No one has really answered this question. Just because some thing changes colour or "reacts" with something in your mouth when you spit it out, doesnt necessarily mean that it is "crap" from your mouth. It could be something as simple as it reacting with naturally occuring saliva. The sellers of Dentyl know that it looks great and is presumed to be working when you can "really see" it working! What i want to know is whether the pink crud you spit out is actually "proof" of removeal of crap!