I add half a boxduring the wash cycle to kill any smell from the drum, then add the other half during the firstrinse cycle, most of it rinses out during the second rinse leaving only a slight residual amount. "Whitening" has never been a problem from my observations, and the residual soda keeps killing odor while I wear the garments. Unlikethe unverifiable claims of ScentLok and other carbon garmentsthe odor protection is infinitely renewable throughout the life of the garment when using baking soda, and at 50 cents per box isconsiderably less expensive.