As part of my downsizing and cleaning has involved me digging into little baggies and boxes full of parts. I’ve found a lot of couplers… no that’s not enough emphasis.. a lot of couplers and even more coupler boxes!
The container is a dremel bit container, my initial idea was to use it to organize some smaller parts but never ended up doing it till now. I found an amazing number of Kadees and even more decent plastic couplers. I prefer the metal Kadees but keeping around the better plastic couplers just in case has come in handy. I know I have a number of regular runners that are rocking plastic couplers because I didn’t realize I had Kadees so that will soon be fixed.
Matt's Railroad Blog 
It was always the way that my collection of Kadee #5 coupler boxes accumulated quietly over time that surprised me most of all. I can’t imagine what I thought I was saving them all for.
It’s so nice to have things organized, not just as a means of knowing what you have but so that these things are at the ready when you have a minute to work on a model.
Great stuff.
/chris
I’m not sure why I had so many coupler boxes but at one point I was using them to modify mdc/roundhouse ore cars by cutting off the cast coupler box and fitting a shortened kadee box so they were closer together… A project I found in my cleaning and had mostly forgotten about
Eek, I last worked on them January 2013… too many unfinished projects š
https://bestsnowman.wordpress.com/2013/01/03/improving-roundhouse-ore-cars/