Answered by Shaykh Faraz Rabbani
If someone has dried urine on his hand (no moisture), do the things he touches with the impure hand also becomes impure (like clothing)?
Walaikum assalam wa rahmatullah,
I pray this finds you in the best of health and spirits.
Touching dry with with a dry (or moist) hand is not considered to transfer the filth, unless the traces of the filth (color or smell) appear on the hand. [ Shurunbulali, Maraqi al-Falah ]
And Allah alone gives success.