use only alcohol for ink mops, and only paint thinner for paint mops those are your solutes for the two different types

 

Try to use a chalk board eraser or dry eraser instead of the sock. They are thicker and won't drip or bleed as much. Meaning you won't lose as much of your ink.

 

I made the same thing but I put a sponge with a sock around it for my first mop a year ago. But it stores too much and when you press it up against a surface it all comes out and drips on the floor and you loose a shit tonne of ink/paint. Try to use something that doesn’t hold as much of the ink/paint in the nib to avoid getting it all over your legs and hands.