General information:
The bottles are no brush bottles, this is intentional.
According to the manufacturer, contamination can get into the bottle via the brush.
This can cause the opaquer to thicken; this applies to all air-drying opaques on the market.
As an aid you can use a small amount of silicone to form a potty when making silicone matrixes.
These homemade pots can be used in many different ways in the laboratory.