If a long metal pipe used to hang towels in the bathroom becomes impure, can it be purified by drying, by analogy with impure ropes?

This statement is based on the purification of something that has become impure by means of the sun and dryness, which is a recognized opinion among scholars. The same applies to the metallic tube of a towel rack. There is no harm in acting upon this opinion. It appears that you are experiencing intrusive thoughts (waswasah), and we advise you to adhere to supplication and humble entreaty, and to distract yourself from these intrusive thoughts. We also recommend that you consult a trusted psychiatrist, and you may also refer to the consultation section.