Figure 1.

Experimental design. Six towels were prepared for each household. Three towels each were prepared with red and blue tags. Each towel was labelled from 1 to 3. Red-tagged towels were used in daily life and washed repeatedly, whereas blue-tagged towels were not used but were washed with red-tagged towels of the same number to evaluate the transfer of grime and microbes while washing. Towels were collected every 2 months and used for various analyses (orange boxes) with methods shown in blue boxes.