In Europe it's pretty common to see sawdust (yes the thing you buy for your hamster) to be put in the boot of CV joint when selling used cars. The reason for this is that when you go check the car the CV joint stays stiff and doesn't click and make any suspicious noises. This "fix/trick" works only for few days of driving just until you buy the car from someone and get scammed.
My question is how to spot the sawdust in CV joints?