Also keep in mind that the fossils, embedded in silt and clay, should be as dry as possible since water will react with Rewoquat to a hardly removable gel. Rewoquat will not work with clayish matrix with high content of glimmer minerals (mica). For very delicate and fragile fossils it is recommended to dissolute Rewoquat to a 30-40% solution. Just leave the fossils in the glass jars with Rewoquat over night. Rewoquat dissolutes in very hot water (at least 60 degree Celsius, better 80 degree Celsius). That way you can clean fossils from Rewoquat. Then you just have to store the fossils in a jar with water and the rest of the gel will move up in the jar as tiny clouds and you can easily remove it. You can reuse Rewoquat since the silt and clay will sink down in the solution. You can use one jar with Rewoquat for about 20 times, then you need to clean it. Just let it stay until the mineral fraction is completely separated from the solution at the bottom of the jar and carefully decant the clear Rewoquat. That way you can use it for years. It might get thick over time but you can easily dissolute it again with Isopropanol.
Cheers
Ronny