How to create a burnt celluloid effect?

I have been scouring the web for a plug-in to enable a transition between 2 clips where it looks like the celluloid film is melting / burning the first clip to reveal the second clip. I haven't been able to find any plug-ins, only stock footage with a chroma key matte - but that lays a black bit of melting film on top, rather than using the outgoing shot as the shot to be melted.

Any links, tips, suggestions welcome.

Thanks!

There might be a way to work around that, depending on the clip. Do you like the look of the stock matte otherwise? If so, seeing the clip in question would help.