I rinse with hot water, add BLC and let it sit 10-15 minutes, rinse with hot water, sanitize.
From NB website:
"Liquid cleaner for draft system lines, including tubing, faucets, and valves. Make a solution by mixing 1 oz. per gallon of warm water, and pump it into your beer lines. BLC needs 15 minutes of contact time to remove deposits, beer stone, etc. Rinse with clean water."