Metal Glitter in brake fluid

Has anyone experienced Metal glitter in their brake fluid before?

This is an issue I keep having with these BAER SS4 calipers.
This has persisted through multiple different master cyl, and even 100% full car new brake lines.
the glitter is building up in the caliper, and JUST the rear calipers.
I cleaned out the calipers 2 times and replaced seals 1 time, and can't figure out what's going on.

the caliper itself is fine on the inside with no signs of wear.
the piston bores are the same diameter (1.378in) after 1 race season.
The pistons aren't stainless, but they also show almost no wear.
the car is a 1992 Camaro with these aftermarket rear BAER brakes.
tracked 5-6 times a season and runs about 250 autocross laps.

Two questions:

1.) Do you have small children? If so, that's why there's glitter in your brake fluid.

2.) Is it possible that DOT 5 was mixed with some other type of fluid? My understanding is that they're never to be mixed, but I'm not sure what actually happens when you do mix them. Does the resulting mix just eat at the insides of the lines? My guess is that the metal glitter is the inside of your hard lines. But I don't know--I've never seen this before.

See if it's magnetic. If you can identify what it's made out of, it might help you narrow down the list of possibilities.

In reply to confuZion3 :

I've always used the Wilwood 600+
It's the same fluid like 5 companies re brand as their own 600F fluid haha.

It's not magnetic, I assume it's aluminum but no idea where it's coming from.
somewhere inside the caliper.

 

I haven't seen that before...given everything you've changed it could only be coming from the rear calipers or something in the middle of the system like a brake proportioning valve, or an ABS system if you've added one. Maybe at the next fluid change try disconnecting the rear brake hoses from the caliper and see if any glittery fluid comes out of there, that way you could be sure it's coming from the rear calipers. Is the glitter attracted to a magnet? That could give you another hint to where it's coming from.

Edit: Whoa, buncha posts in the last few minutes! Being non-magnetic that suggests that it's the caliper itself. If it happened once I'd think it might be left over from manufacturing, but happening multiple times suggests that it's coming from some kind of wear...

I've never seen glitter in brake fluid. My first guess would be that it's wear debris from caliper bore.

Master cylinder piston would be my guess. I would look for wear there. If the chrome finishing on the pistons and calipers is clean. 

Any chance you are putting a angular force on the rod to the master?

i apologize ahead of time if im posting this in the wrong are but im just tying to give and take a little bit on the glittery brake fluid. ive never raced before, but i am here trying to find answers to the same subject. but mine is on a 2015 Cadillac escalade. there is the glittery brake fluid in the resevior and you can only see it when you shine a flashlight across the fluid. it has steel calipers up front of course, but it has the alluminum calipers in the rear. I wouldn't think that the metal would travel all the way up to the resevior unless of course it was coming from the resevior. all this being said, i will look further into it this weekend as to the escalade isn't my vehicle, and I won't see it till sunday. I appreciate your conversations, and if you're interested in what I find, I will let you know when I know more.