It would probably be easier to replace it. Sometimes the growth can permeate the vinyl line and it is impossible to remove the taste. Check the connection behind the faucet. You may need to cut a clamp and then the line off of a barbed fitting. Then re-clamp the new line back on. The connection at the coupler is much simpler as it is either a hex or wing nut fitting. Be certain to replace the beer washer under this fitting. Check out this link for
beer line .
Scott Zuhse, Instructor
Micro Matic Dispense Institute