Once they crack or get chalky, replacement is really the only option worth bothering with.
The removal process is pretty straight forward but it's a lot of work and fiddly to avoid scratching up the fiberglass.
You can get replacements going online from many sources. They all tend to hold up for maybe 10yrs if you aren't storing inside. An alternative if you just have big swooshes is to tape around them prior to removing and then you can paint them back on. Use a good high quality paint (Brightside by interlux is good) and they will hold up for a long time and it's easy to do touchup if they get dinged.