I had a tin of the wartime US gas detection paint. It took quite a bit of stirring, but it eventually mixed up just fine. I used it to paint the upper headlights on the two M20s I owned, and the inner area around the "invasion star" on my WW2 Jeep.(As seen in color photos taken at the time of D-Day) The star emblem had been sprayed onto the O.D paint of the hood using a stencil, using plain flat white Rustoleum paint. I found that if I touched the white paint with the gas paint, it turned a bright pink! I ended up having to paint the whole hood again, being very careful to stay away from the white paint of the star emblem.