There are some fillers here, notebook jottings that might chiefly interest somebody like myself with a professional interest in Sinclair's work.
We use no binders or fillers so the capsules are 100% pure finely milled graviola powder.
We refused to use any preservatives, fillers or binding agents.
I think some of the fillers used included slag and ash from iron works and coal fired power stations.
If the counterface is plastic, then you should determine if it has any fillers which could cause abrasive wear.