What is the ruling on dry dog impurity on clothes if a wet or damp garment touches them, and is it permissible to adopt the more lenient opinion due to obsessive thoughts about purity?

Dry pure matter, if it encounters dry impure matter, does not become impure. If you doubt whether your clothes have been touched by dog impurity, the default is the certainty of purity. Whoever is affected by any dog impurity must wash the affected spot seven times, the first time with earth. However, some scholars do not deem it obligatory to wash seven times or with earth. The one afflicted with obsessive thoughts (waswasa) may adopt the lighter opinions, such as the opinion that wet impure matter does not make something impure upon contact, or sufficing with washing it once. The one afflicted with obsessive thoughts is advised to supplicate, humble themselves, distract themselves from the obsessive thoughts, and consult a psychiatrist.