i have a washer drain where the drain pipe leads into a gravel filled barrel under my patio. I'm sure that the barrel is filled with lint. it does not properly drain under the volume of water the washer puts out, and the drain overflows. i have tried snakes, drain-o, and other drain opening solvents. i want to know if there is a chemical that is great for destroying lint or if there is any other solutions for this problem without demolishing my patio.