Hi MVEBA,
Thank you for using the Support Forum. I cannot recommend that you alter the ink from the 8400 to fit in the 2424 as it could cause damage to the machine. Please consider contacting the supplier to see if you can return the unused supplies for credit.
I have ink left over from an 8400 that is in the trash. I have a 2424 and wonder how bad an idea it is to trim 8400 ink to fit C2424. It seems if I am careful to have to nub on botton of cube to ride in track I should be OK.