costing run for co-product

Hi friend,

I have 5 different finished materials each having 2 same co-products. i could do the costing run for the finished materials, but how to the costing run and standard cost estimate ( i.e ck11n and ck40n) for the 2 co-products. the co-products does not have BOM and routing.

Regards,

Arun kumar R V