I have a double action gravity fed brush, I don't know the brand. I had used Vallejo color master gold thinned with Vallejo Airbrush thinner. The paint did not come out. I have thoroughly cleaned the brush, disassembled, brushed the nozzle, wiped down the needle, brushed out the air duct from the hose to the nozzle, reassembled and tried to run some Airbrush cleaner through the brush, but nothing comes out but air. Bubbles come into the reservoir if I cover the tip. I will get some fluid out if I pump the trigger. There are still tiny flecks of gold floating in the reservoir. HELP!