Four words.... I love these things!!! I didnt run into any problems except the drip issue in the tip of the marker.... Just dont be a dumb@ss like me and fill one with latex paint.(bought the wrong kind)
My suggestion is silver Rusto (4 parts)
Paint thinner (1 part)
Dot 3 brake fluid (1 part)
Oh! And when you go to take the top off to fill it, DONT LOSE the mixing balls, as they WILL fall down the drain. just use a strainer to catch them.