If your worried its not clean inside try some of this.
https://airbrushes.com/product_info.php?products_id=572
Strip the brush right down, and spray tge small parts in the lit off of the can. Then fill the bowel and area where the trigger assebly goes and repeat a couple of times. You can use these
https://airbrushes.com/product_info....d58aea4f81a80f to go through the small holes and clean the larger chambers with a cotton bud.
Hey presto it should be like new.