If you get grease-like marks on your clothes after a laundry cycle, and they wash out in the next load, don't despair. It's a sure bet they're caused by detergent and fabric softener that have congealed on the underside of the agitator or along the top edge of the washer basket.
To eliminate the problem, first clean any crud from the gap along the top of the washer basket. Then remove the agitator and clean the gunk off the underside. Since the agitator removal procedure varies by manufacturer, go to allplianceguru.com and search for your make and model. After youve cleaned the agitator, reinstall it and fill the tub with hot water. Next, dump in 8 oz. of washing machine cleaner (Washer Magic is one brand; buy from amazon.com or applianceparts stores) and run it for a full cycle without any clothes. That should eliminate the problem. If not, repeat the procedure.