Sulfuric Acid Drain Cleaner =link= -

It is highly effective against dense hair clogs and paper-based obstructions.

Disclaimer: This content is for informational purposes only. Always read and follow the manufacturer’s safety data sheet (SDS) and local plumbing codes. sulfuric acid drain cleaner

Sulfuric acid doesn't leave a tunnel . It floods the entire pipe diameter, dissolving the walls of the clog equally. For a single, stubborn, organic blockage in a metal pipe, where snakes and enzymes fail. It is highly effective against dense hair clogs