Rust Spread to Symbols? And other rust questions

[WaterDraw]

As some of you who might read my posts know, I have a Bridal Beauty with tail rust. As I was photographing her and upon closer inspection I noticed she has this weird mark on her symbol, a rust colored mark. Can rust spread from the washer to the symbol? I know that some ponies with the glitter symbols can have their symbols rust but can the same be said for normal ponies?
Also;
How can you tell if the washer has disintegrated?
How can you tell if the mane is rusting (I can never see it, even in a video where there was a pony with mane rust)?
Is there more information about rust I need to know?

I still find rust one of my biggest pony fears, but I am slowly starting to get over it. Just touching her today was like a big step for me. (I know that probably sounds stupid but it was an accomplishment!)
Any help is appreciated!

[banditpony]

Clean her out. She's most likely full of rust on the inside, and that's what you see on the symbol.

Only metal can rust.

[Elfpony]

If you see tail rust then you know the washer is in some stage of disintegration. Rust will not spread off the metal, but as the washer breaks down, the particles of metal and rust will flake off and spread throughout the pony. There’s nothing on the mane to rust, but these particles will get trapped in the mane. Rust also stains ( which is probably what you see on her symbol) so it’s a good idea to clean her out and remove the washer. She may be quite black on the inside due to the rust. Whitening toothpaste can help to reduce the stains, but it may also fade colors (especially fading pink hair.

Elf

[Safflower]

Rust probably stained the symbol, just like it could any other area. There is nothing in her symbol specifically that could rust, though.

Like others have said, clean her out! You have no idea how bad it could be inside.

Also, the mane cannot rust. There is no metal there, but the washer rust can get up in the head and into the hair. If you can see that the bases if the plugs look dark, the rust is probably bad since it got up there.

You can't really tell how far gone the washer is until you open a pony up. The washer could just be a tiny bit rusty with the majority of the metal still showing, or it could be completely gone with the whole inside of the pony coated in flaky rust. If there is rust though, you should really open a pony up! You have no idea what is going on and it's best to clean it early rather than to let it develop.

[WaterDraw]

Okay everyone, thank you for the advise!
Now I have just one last question.

So since Bridal Beauty has tinsel in her hair and I need to soak her in order to clean her, would it affect her tinsel? Like would her tinsel be ruined by doing the treatment?

[lovesbabysquirmy]

Tinsel will not be affected by any of these treatments.  Just don't PULL too hard on it or the plastic stretches out. 

[WaterDraw]

Tinsel will not be affected by any of these treatments.  Just don't PULL too hard on it or the plastic stretches out.

Okay, thank you for letting me know