There are specialised microfiber rejuvinators for this purpose from almost all famous product lines but ofcourse we'd rather get something more useful than getting a washing soap 
As suggested by Ahmad bhai (and tried by myself), soak the microfiber in either a liquid hand wash OR wash them with sufi soap (yep, you heard that right). I clean my MFs with sufi soap, gives you more control for spot cleaning on the dirty areas and towels dont really give a dried up look after the wash.
DONT'S:
Make sure you wash the microfiber either separately or same brands together. Also, do not use a bleach or fabric softner as that will kill the static charge in the towels making them ordinary towels. Dont heat dry them and dont put them in a drier as well. But make sure wherever you put them for dry is less dusty as it would continue to attract dust 
