Q: Does one have to wear leather socks to do masah or can you do it with normal cotton socks instead of leather socks
A: Masah is only permitted on leather socks, or any socks that are as durable and strong as leather, such as seal skin or neoprene socks. Masah is not permissible or valid on cotton or nylon socks.
And Allah knows best
Mufti Siraj Desai