To answer your question:
Yes you can. I have developed Kodachrome 64 to B/W by way of CaffeinC developer, a mix-it-yourself solution, where you buy washing soda, vitamineC (100% powder, not pills) and instant cofee, mix it after a specific recipe and develop.
I ahve done it and it works.
Only trouble I had that noone on the caffeine group could explain, was a pitch black layer that did not come off at first, I discovered that when I was about to dry the film. Quickly reimmeres the film into the water and applied a little force with wetted fingers and the black layer came off, the negatives where just fine.
JUst look up the APUG group for this for further explanations, in there is also a link to a guy in germany who is developing this to an art, but the guy in question has never developed neither K64 nor K25 to B/W.
I have another roll sitting here, that came3 with an old camera, that may or may not contain images, I will do this roll when I have extra space in a tank, the amazing thing wioth caffenol is that you generally get away with the same temp/time for nearly all films!
Erik