Hi,
Thanks for writing. It sounds as though your plant may be infested with spider mites. These tiny, nearly microscopic, critters can be very difficult to get rid of. If your ficus isn't too large, I'd take it outside or in the sink or shower and wash it down once a week or so. If you keep this up for a month or so, you'll get rid of the spider mites. You can also spray for them using organic products such as neem oil or insecticidal soap. The key is to be consistent --- sprays kill the adults, but not the eggs. So after you spray the eggs hatch, become adults, start mating, and lay more eggs. But if you attack them every week, you'll decrease the populations until you've killed them all.
---Justin, Senior Garden Editor, BHG.com