Attached is an image showing two years worth of scroll pump tip seal (PTFE) wear accumulation in the scroll pump used to back our VBOD RGA turbo.  Unlike our typical scroll pumps which experience viscous flow from time to time, either as the result of rough pumping a volume from atmosphere or from an introduced ballast purge, this pump has never experienced viscous throuput. 

The "amount" of wear (dust) is normal and is a function of run time.  Of interest here is the degree of accumulation and not the degree of generation. 

Note that this dust would be "blown" out of the exhaust port if/when this pump were to pump a viscous load :)