How should the wipe be folded during sampling?

• A. Fold the wipe in half, clean side in
• B. Fold the wipe in half, dirty side in
• C. Fold the wipe in half, dirty side out
• D. Fold the wipe in half, clean side out

Answer: (B)

In wipe sampling, the goal is to prevent contamination from spreading and to keep the surface you wipe with free of contaminants. Folding the wipe in half with the dirty side tucked inside creates a sealed pocket that contains any residues, so they don’t reach your hands, the surrounding environment, or the surface being sampled. The outside surfaces remain clean and are the ones that contact the area being wiped, helping to preserve the integrity of the sample. If the dirty side were exposed on the outside, contaminants could transfer to you or to equipment, compromising both safety and the sample. Folding with the clean side inward would also expose the dirty surface, increasing the risk of cross-contamination.