Digital BW, The Print

Please excuse me if this is posted more than once - but it didn't 
appear after quite a while and I've re-posted

Can the CIS carts (from MIS) be cleaned and then re-used with another 
ink ?

I had the wrong inkset delivered and 2 (the C & M) of the 4 inks are 
being exchanged.

I had already filled the new carts using the vacuum method via the 
top tubes, so the bottom seals are unpunctured and still intact.

I managed to draw the ink back out of the 2 cart chambers (C & M) by 
pulling it up the tubes with a syringe, but a wee bit remains.

How can I clean this up,  or is it better to leave it and refill with 
the new ink and let them mix until it's exhaused and replaced from 
the bottle?

 I have to pull a vacuum to refill these 2 chambers with the 
replacement ink. Is it possible with a little ink still in ?

And, can the tubes be removed from the cart end, flushed, and 
replaced - by heat ?

thanks in advance for any tips.