There is no need to fit a scot-oiler and I know some people love them, but I hate the things.
I am a courier and have one on my CBf, even on the lowest setting the bike is always filthy at the back end, the rear wheel is always black, and the amount of gunge I have to get off the bike is really annoying.
Whereas my non worked VFR doesn't have a Scot-oiler has done about 40 thousand miles and the chain is still going.
And the rear wheel stays a lot cleaner
The VFR has for a while lived in a very salty environment yet with barely the minimum amount of care the chain still has plenty of life in it.
Going to your original post and replies:
Nothing wrong with using WD40 as a chain cleaner but you don need to then oil your chain afterwards.
I would use a decent chain lube, currently using Hein Gericke chain lube, its good enough.
As mentioned, pressure washers sound like a good idea but are often or not too powerful especially on chains and radiators etc, and to be honest too powerful for a lot of paving slabs as they take the skin off the cement and then you get early wear.
I wouldn't buy one, yes they look like they are quicker, but for bike washing you are probably better off with a bucket, that's what I use.
Give the chain a really good lubing, making sure you get the lube between the plates, then take it for a run to get it warm, when you get back as soon as you can, put a bit more lube on.
Leave it for a while then run it again and your chain should be OK as long as the O-rings weren't damaged.
And Hello Jack, hows it going mate (Bob here, Yellow VFR, called by your house for a cuppa a few years back).
Bob