I use army painter after I've finished painting. Because it comes in different shades, you have to realize that it'll only work well with certain colors. For example, if you paint a mini white, don't use the Strong or Dark tone on it as you'll badly tint the white. There are a few different ways to use it, including dipping and then shaking off. I once sent an unseen Rifleman flying into the grass with this method... I'll never do that again.
I prefer to brush it on the mini with it hanging upside down over the tin. Start from the feet and brush down to the head and then brush off the excess. This way, it darkens shadows nicely. You'll be there brushing off excess for a while as if too much pools you will obscure detail. And unlike wood, you can't just get fine steel wool to smooth it out again. Once it is dry and hardens, you'll have a nice and solid layer of protection. I then use a matte varnish to get rid of the shine, then paint cockpit glass and jewel anything. I finish with painting those features with a brush-on gloss varnish. You can paint over the Minwax/Army Painter, but you get bad adherence and it takes more coats than it should.
For cleaning, I've found isopropyl alcohol is the best for brushes. You can mess with thinner if you want, but the alcohol is the easiest.
