af90 hit it on the head.:xyxthumbs:
I might add that if you don't have a dedicated MF detergent that a mix of Woolite and your normal liquid detergent (try to get one that doesn't have a ton of scent to it) with just a couple spoons of white vinegar will work GREAT.
If you are lucky enough to have a washer where you can program custom cycles that'd be great as well. Ours we can, and I setup 2 microfiber towel cycles, one with a pre-soak stage (for the extra dirty towels) and one without.
Ours will weigh out the load and decide at that point how much water to put in. I'll trick it by putting the towels in and then pouring a couple gallons of hot water on them.

That way I get enough water to cover the towels on the first wash/fill.
Have it set to do the wash, extra rinse, extra spin, gentle cycle (but not delicate). It'll then transfer it's data to the dryer (via serial cable) and the dryer know what to do. (Basically, if you have a polyester cycle THAT is what you want to use.) Low heat, moisture sensor set to at least next to, if not the driest setting.
The CRITICAL PART however when washing your towels is pulling them out one at a time and inspecting them both BEFORE and AFTER you've washed/dried them. Lay each towel flat, do a visual inspection, pick off any little pieces of trash, dirt, contaminates, anything that sticks in the fibers. Then slowly and carefully rub your open hand over each towel feeling for any snags or bumps and immediately pull the offending matter from the towel. Do this to each side, and like I said... do it BEFORE and AFTER.
It also helps you to keep an eye on the condition of your towels. It's easy to "grade" them and make that decision during the cleaning cycle as to what units will be "paint quality" the next time you use them. Nothing will tick you off more than getting right down to the LSP stage of an all day detailing session and having a towel lay down a 12" RID right across the hood because it had a hidden piece of leaf or trash or sand holding tight in the weave!