Digital BW, The Print

Hello friends:

The PK cartridge on my 4800 is about to go dry (6%). I have wanted to switch back to MK ink, 
but have been putting it off till now. What do you think if I just switched the ink cartridge and 
NOT do an official purge 'n' switch, allowing some printing to let the printer move what is left 
of the PK ink out of the lines? I realize I may not get optimal results with the MK ink until 
about, what, 10-15 ml of that black ink has coursed through its veins. But will I be damaging 
anything?

Thanks!