Digital BW, The Print

This is another topic I seem to remember seeing discussed somewhere 
but, alas, cannot find.

I am accustomed to swapping out photo black ink for matte black ink 
Epson cartridges when I use different papers.

Now that I am usuing MIS inks, the printer obviously is not being 
used for color....but I still have this array of color inks in 
plastic wrap just sitting around.  I have noted that the MIS inks 
will leak if removed and not handled carefully.  The question:

Is it practical to swap the ink SETS in and out for those times I 
want to do color?  Obviously, I know it can be done, but will there 
not be problems with old inks in the nozzles (like the B&W inks) 
such that when the color inks are put in there they mix into a mess?

Thanks for all the great help from this group!