Scrims (eugh, nasty things!)
A cool wash is fine, just on a rinse program with no powder or softener - there's normally enough soap in them by the end of the day anyway. Once the machine's finished, (check there's no dirt still in the bit just inside the door, if there is just put them on again) give them an extra wring and a flick-out then hang them up to dry. Don't put them in the tumble-drier - well, go on then and find out why!
Microfibres
Same again - remember that conditioner ruins them, it clogs up the fibres - every so often you can stick them in a hot wash, I think they can take 90o
I put sill cloths in for a rinse or two then add the others.