How can a mobile phone that has been touched by madhy be purified, and does touching the phone after ablution for prayer nullify the ablution?

If you touch a mobile phone with a wet hand that has impurities (najasah) on it, the phone becomes impure (najis) and it is not permissible to carry it during prayer unless it has been purified. Its purification is by wiping it if washing it is feared to cause damage. However, if you touch it after the impurity has dried, nothing transfers to it. Touching an impure device does not invalidate ablution (wudu'), and it is advisable to be cautious of obsessive doubts (waswasah) in these matters.