If you find that a certain paint just keeps making your airbrush spit, it may have curdled. If there is air in the bottle can start to cure in there. Perhaps there is air in from the factory. I have had this when I half used a bottle and then left it a few years. Lumps come through and block the brush.
First, give the lid a thorough clean with some pipe cleaners.
Prepare your bottle like it's going to rob a bank with some tights (I believe pantyhose is the US term).
Screw the lid over the top.
Trim the hosiery.
The newly installed filter will prevent lumps escaping the bottle.
I intend to do this pre-emptively on all bottles I have opened. Just as soon as the Mrs gets some more ladders. (I don't look fabulous in hosiery).
I thought I would write this one up, as I don't like to watch videos where I could have got the info by skim reading much faster.