Hi Emily, Happy New Year, I use a pressure washer on mine!
2013 photos & vids here
eff37 on Flickr
Hi Wendy, does the pressure washer not take all of your paint off though?
Not that I've noticed Emily ...very good for getting rid of green algae on untreated wood surfaces & use it on painted wooden walls of mobile home to no detriment!
Ah I'll have to buy one and give it a go. Can I ask which one or which brand you use?
Can't remember for the mo, it was a good offer from local DIY store couple of years ago now, but not Karcher which is the most well-known! Try a test patch first Emily, might depend on what paint has been used!
Thanks Wendy I'll give it a try.