Just browsing brewhardware.com and saw this new beauty, https://www.brewhardware.com/product_p/camtoball.htm (https://www.brewhardware.com/product_p/camtoball.htm) just connect it up to your chugger pump and it will clean beer line in no time. He seems to come up with the most innovative homebrew products, just wish it was easier to get them to Ireland.
Carbonation cap will do same thing