I use Minwax PolyShades varnish for my dip. There are several brownish colors and finishes available. I have Antique Walnut Satin.
In the picture, you can see the Minwax, a figure-holding "ladle" that I folded from chicken wire, plastic glove for touching figures without messing up my hand, rubber mallet to reseal the can, screwdriver to open the can, and an old bristleless brush I use to stir the dip.
I get everything ready on some newspaper. I don't shake the dip or turn the can upside down, as this makes a whole lot of bubbles. I stir with the old brush, making sure to mix in plenty of pigment from the bottom of the can with the thinner liquid nearer the top. Note: As you use up the can, you need less of the bottom material; I think too much makes the dip lumpy and too dark.
I place a fig in the ladle, or basket. You can see how thick the basket is with dried dip; I have used it many times, mostly for 28mm figs.
I lower the basket into the dip just low enough to cover the fig, and then immediately pull it back up, slowly. I let it drain for a moment, then I grab the fig with my gloved hand and turn it to the side to drain more.
I place the dipped figs on newspaper, preferably the slick paper ads, so the bases will stick less when they dry. I shove the figs around with the old brush to get them out of a pool of dip. I also use bits of paper towel to soak excess off of the bases and low areas where the dip will settle and look way too thick, dark, and muddy. Some of the places I have learned to watch are lower parts of shirts, cloaks, capes; bottom of shields; weapons, especially those held horizontally; small openings where the dip can dry into a muddy "window" if the surface isn't punctured when wet. Depending on the size and complexity of the figures, you may only dip a couple before starting the clean-up. The older or thicker the dip is, the quicker it starts to set and get so thick that you can't wipe/soak it off with a paper towel.
Once the figs are cleaned up, they must be left to dry for at least twelve hours. Notice how much darker they are! This depends on the amount of folds and crevices on the figure, and is to me a reason to paint with lighter and brighter colors. The rightmost cavalry fig is the one I had left white, with the black spots to cover the stray blue spot.
You can see how the dip has filled in many spots that were missed in painting, and has added some shading and picked out detail.
Here are the figures after they dry. I did not wipe off the chests and upper backs of the crossbowmen enough. I will touch up just a bit with some more silver.