After I got Captain Kirk back on track, I had all six bogies from my three boxcars ready for some weathering with that Frosted Glass spray paint.
First up I used two thin strips of masking tape to hold the bogies to a strip of plywood. As well as holding the bogies down the tape was protecting the axle bearing caps of the bogies so they wouldn't get clogged up with paint.
Once taped down, another strip of masking tape was then used to cover the couplers as they also had springs in them are are quite delicate looking and I bet a coat or two of paint would stop them working.
I gave the bogies four swishes of paint. So there was a left and right pass of the bogie sides and then one angled at each end. The end result is a very nicely grayed and dirty bogie. See them here compared to some unpainted ones.
Last but not least - a hint. When you drop your can of paint in warm water, make sure it is just that... warm and not hot. It would appear that my "washing up" warm is tooo hot. All was well until I removed the paint from the "warm" water and started shaking it extremely vigorously. When the ball bearing inside started to really pound around I heard a pop, then another. When I look at the can, the bottom was like this, so I reckon the pressure was a tad high. Next time I will just keep to warm and not too warm - and based on the usage data, that is below about 40 degrees.