I don't think you will be able to cash it in free
of any fees unfortunately (if anyone knows of a
way, I would sure like to hear it too!).  But, you
should be able to deposit into your bank account
(I did that with GBP and they converted it to $$).

What I would do in your situation is either return
the check to the buyer and ask for a money order
or cash or just deposit it.  
The current exchange rate is:
USD 60.00  =   2,066.77 BEF

Maybe someone else passing by would be able to
help you better than I can.  Best of luck!

Star Phoenix