I brushed on the Army Painter Dark Tone as suggested in the instructions. At first, I thought I'd made a huge mistake as it basically came out as a big black puddle on the first figure but as I spread it around the figure it became more bearable. And then all of a sudden it was "wow" this actually works!
I really don't think that actually dipping the figures into the can is a great idea as you'll get way too much onto the figure and need to brush it off. And this stuff is horrendously expensive for a tin - £18.00 for 250ml - so you don't want to waste it. On the other hand of course it will do hundreds of 15mm figures - on the tin they say it will do 200 figures if you dip - so I'm assuming if you paint it on to 15mm figures you could double that. And 400 or so figures is about five years production for me.