What about  a small patch of thicker dull black anodized aluminum, or even better, blackened copper?  The marks I generally saw on my plane and others looked to be primarily melting the plastic.  I recovered our dash's plastic that had several melt "burn" marks with leather and ended up with one more scorch mark on it -- not a big one, but still visible.  So my t thought is that if the aluminum is thick enough, it will conduct the heat away and spread it out.  That's why the alternate material of copper would be even better, very high melting point, and better heat conductivity.  What I'm less clear on is the black copper coating durability.   Anodized aluminum coatings are extremely robust.  So the best of two worlds -- bonded aluminum/copper sandwiches like our "silver" coinage.  The anodized aluminum up, and copper underneath?
Regards,
Charles Patton  ex-LN2 owner