I did my pre-winter ACF 50 treatment last weekend.
Started with a really good clean, trying not to get distracted by detailing, just getting all the muck and grease off so I've got a good clean base to apply the ACF-50 to.
Then once clean and dry masked off the brake discs and callipers with newspaper.
Sprayed directly from the can on to the engine block, exhaust headers and can, the electrics up under the tank, the electrics under the seat, the rear suspension and linkages etc.
Used a cloth to spread around as required, by which pint you have an ACF-50 soaked cloth you can use to apply to more sensitive areas near tyres etc.
It goes on like a light oil like WD-40 or similar. If you've ever used on of the PTFE based predecessors it's much the same. Don't be shy with it.
It brings the black plastics and engine block up a treat, all looks nice and shiny after you're done. Things are left a little greasy but not so much as to be a problem.
Left it for a couple of hours because I always worry about fire, but then test rode it and no problems with electrics etc, although rather a lot of smoke!
Naturally the exhaust headers soon burn it off, but I think a proper coating as described above followed by a quick treatment once a month a so during winter is £15 well spent.
Andy
Oh just to add that I've never had any problems so far with it on electrics, felt a little nervous spraying it on the relays and spark plugs etc but it's been fine so far.