I haven't made any goo, but there are recipes posted here. Scroll down and look at the bottom of the bar on the right, you will see a link to "lava lamp formulae" where you will find several to try. You can also search the discussions and see who has had success with the different methods.
Modulo '70
Mar 2, 2009
Keith
Mar 3, 2009
Keith
Mar 4, 2009