Small loads of towels (<12)
The MFs used for glass cleaning, dusting, or general interior cleaning (auto or home), I toss in with T-Shirts or jeans. Warm wash, liquid Purex, 1/8 cup Borateem.
Those used for lower panels or wax removal are soaked overnight in a solution of liquid purex and a small amout of degreaser (NOW or a di-limonene product). Rinsed twice by hand and then put in the washer alone. Again warm wash, liquid purex (no Borateem). After washing these towels, I always wipe down the inside of the washer tub (just in case any residue remains).
I usually air dry unless I have a load of more than a dozen. If I put them in the dryer, I wipe down the dryer to remove any possible fabric softener residue.