Since the OP started this thread be cause he life
lines were dirty/ugly, I would recommend a product called "Awesome" (I didn't name it) from the dollar store. It is hands down the single best plastic/vinyl cleaner made. Best part, it is 100% natural and only costs $1.
I would investigate weather their is need to replace the lifelines. If any corrosion exists, replace 'em. If not clean with "Awesome" and go sailing.