I wouldn't try burning anything other than white gas. There are some Primus stoves that look much like a 123 and burn kerosene, but I have no idea if the jet from one of them would fit.

The MSR XGK has two jets-one for kerosene and one for everything else. The kero jet has a bigger hole since the fuel vapor is denser.

I used methylated spirits in my XGK, which you aren't supposed to do, but it worked. Meths is denatured alcohol with usually some coloring added. It might work in a 123-the burner design is pretty similar to the XGK, but again, not recommended.