I made collars for our 2 ankle biters, one being a mostly white rat terrier. Took me a while to "finish" them as I would work on them when I had a few minutes here and there over the course of about a month. After they had worn the collars for a few days I noticed the white dog's neck was turning brown in the collar area. Since it had been about 2 weeks from the last time I worked on them until I put the buckles, etc, on I had to think a moment about what was going on. Guess what I forgot to do.