I have been using replenished XTOL for about a year, quite happy with it. The other day my big jug of it fell over on the sink and shook loose some gray granular material, which for all the world looks like very fine (powdery) silver. It is so small my filter funnel won't catch it. I left a gallon beaker full of it for about six hours, and it did not settle out. That evidently takes a long time. I have not noticed any problems, but can only imagine that small spots will result. Is it necessary to filter this stuff out, or just start over with a new batch?