I don't need to remember to flush them anymore.
I disconnected the hot and cold lines that go the W&D behind the basement wall and capped them off with Flair-It RV PEX caps. Did it several years ago.
http://flairit.com/productByCat.php?pcid=6&p=0
Left all of the lines in place and easy to re-connect if needed.
No more stink, no more remembering to flush out the lines, no extra maintenance necessary.