Below is quoted from the Trautman Art Glass website
Ah, Slyme. Ectoplasmic! One of the most unusual colors in the boro palette, Slyme can range from transparent to translucent to a milky semi-opaque, depending on how you work it. Work cooler to keep Slyme more opaque, with a soft reducing flame. This also prevents reboil and scumming. Goes transparent under higher heat, but can develop a ghostly milky green haze. Slyme is known to have a slightly higher COE, so but works in nearly any application.
Especially at the start, you will want to USE A REDUCING FLAME WITH SLYME for best results! You can switch to a bushy neutral flame once it is up to temp. If you are getting scum or boil, check your oxy regulator and consider lowering the pressure at the tank. Slyme tends to prefer a lower ratio of oxy to propane than nearly any other color you will use.
Squiggle by Paul Trautman, Curl by Jeremy Harper"