Passengers boots melting on exhaust pipes. Common Problem?

[Yahmaha]

I have had a passengers boots start to melt and leave residue on my pipes just below their foot pegs. Didn't know what it was at first, but finally figured it out.

It is EXTREMELY hard to get it off. The only think I have found was easyoff oven cleaner, but obviously its very caustic. Any body else experience this? Have suggestions on how to remove it? Will the easyoff eventually damage the chrome?

Thanks in advance.