As mentioned above, detergent is important to release wax/product from the very *magnetic* fibres.
I find the most difficult, and important aspect is the rinsing. Since MF is designed to hold and trap product, getting it to release detergent is the most difficult thing. The more detergent you use, the more it will trap. Using too little will result in the MF not releasing all the rubbish. Using too much will result in the MF trapping all the detergent residue. It's a balancing act.
I tend to use less detergent than regular washing, always liquid, and use hotter water than normal. Not hot, hot, but hotter than normal. This helps improve the detergent action (requiring less, thus less residue) helps dissolve wax/products which responds better too hotter water.
Then, the most important part (to me). Rinsing. I rinse at least
twice with the same temp hot water as before. Again, the warmer water helps release stuff from the fibres. In the last cycle, I add some white vinegar to help with the rinsing. Whether I do one more rinse depends on how much foam I see on top off the water during the rinsing cycles.
I find that if I don't rinse sufficiently, not only do the MF not perform to their best, but can lead to streaking when used to remove LSPs, as the trapped detergent interferes with the product I'm removing.
I don't machine dry...I just air dry inside somewhere (much to my wife's amusment...she's use to it now.

) I find letting it air dry allows me to see how clean and residue-free they are based on how well they cling. I find when I machine dry, the static-cling the machine creates masks the true state of my MF and the success of my process.
I know it sounds quite anal, but...hey! you're on Autopia!
