This is just a quick view in how to remove the airvalve piston and spring on Iwata and other Chinese knock-off. I used my Iwata HP-CS Eclipse for this demo. I just got me cheap tweezers from the local pharmacy. I just cut of the sharp edges and sanded them smooth. Tried to make them the same width as the openings of the valve nut. The rubber o-ring is there to help keeping the tips pinched. This way you don't need to worry about gripping the nut, just to turning it. This is where you need to go into. Perfect fit. Adjust the o-ring so that the tips have a good grip. You will end up with a nut ready to put back. Piston and spring exposed. Very few parts in the airvalve. I do have a Sparmax removal tool but it only fits Sparmax guns. You can modify it to fit Iwatas but not all of them have the same size nuts so you will need one for each gun.