Posted by Jon U. on August 18, 2002 at 15:59:18:
In Reply to: What is this stuff? posted by Sam on August 18, 2002 at 14:50:50:
The green stuff is a sign that you need to get your horn chemically cleaned.  If your slides look like that, that's also what your valves look like.  It's actually sped up by a lack of valve oil.  When your spit dries in there time after time, it causes crud in the valves.  Valve oil causes a barrier between the two.