concrete blocking a U trap

[hendan]

concrete is blocking a 3 inch cast iron U trap that got in when a contractor rinsed his tools after doing a concrete job!! The U trap only has one clean out plug.

Any advice to correct this problem is much appreciated.

[Drew]

There is a product called sealoclean (different companies may use different brand names), that is a brick acid used to clean morter splashes of stone work. This might be worth a try, and should be mild enough not to affect the cast iron.