Don't try it Mike!
The wax will soften and loose it, strength well before it actually melts. 
I can just imagine the mess.
I have 8 supers of solid OSR honey in my kitchen which I am am scraping
down to the midrib with a teaspoon
a long and tedious bussiness. I will transfer the scrapings to my uncapping
tray to seperate the wax later.
I have heard that Willie Robson who runs several hundred colonies up in the
Borders(England/Scotland) just uses unwired foundation
when working OSR and cuts out the lot for melting down at the end of the
season.
I don't think there are any easy answers this one.
 
Regards
Joe Trattle
Norfolk UK
 
>I've ended up with some crystalised oil seed rape honey in some of
>my frames and was wondering about how to extract it.
 
>How about the following idea?...
 
>Put all the offending frames in a warming cabinet (insulated box
>with 2 x 40W light bulbs) for a few days until the temperature
>reaches wax melting point minus a safety margin (any ideas for a
>value here?).  Hopefully all the honey would dissolve back into
>liquid form (reasonable assumption???) at this point.  Now remove
>the frames from the box and let cool for long enough for the wax
>harden up so as to withstand normal extraction forces but before
>the rape re-crystalises.