If trading which is rare now I only use them to detail until such point they become damp.
When using for internal cleans we use slighty damp to clean with vinegar solution and dry to buff.
There are different types of MICROFIBRE cloth, terry weave, flat weave, waffle etc.. Some I can use some not, I hate flat weave personally, plus get heavy weighted brands not cheapo lightweight ones
Wash but do not use softener
Darran