Fiberglass scratch pencil--how do you trim it?

[LittleWatchShop]

A very useful tool...but when it gets dirty and you want to cut it back, I have found it hard to get a nice even trim.

There is probably a tool to do this...lol.

[jdm]

I found that the bristles breaks during use in a way that keeps shape by itself. Great and popular cleaning tool but very dangerous in watch repair. Ask yourself where the fragments are going? Are you willing to use it in a place far away from where you reassemble movements, then clean, blow and inspect everything around, every time you use it? All it takes is a minuscule piece in the wrong place to stop or severely impair a mechanical mov.t.

[LittleWatchShop]

2 hours ago, jdm said:

Ask yourself where the fragments are going?

Good point. 

The tool gets dirty...or at least did recently.  Wanted to remove some crud.  Probably a misuse of the tool on my part. Oh well.

[HectorLooi]

I don't like fibreglass brushes. They scratch up the surface very badly. And those broken glass fibres sometimes get embedded in the skin!  It takes weeks for our body to exfoliate one of these pesky buggers.

I prefer to use brass brushes. 

[Michael1962]

I saw a fibreglass brush on a YouTube video, but did not look any further into it. Did not know that you could get a brass brush. I have some small brushes that have brass bristles much like a normal wire brush, but I think even those would be too harsh on clock parts.

[AshF]

I love my fibreglass brushes.  Perfect for removing rust.  I also have a brass one but it's not as compact or controllable, maybe I need to find a thinner one.

I get what you're saying about the broken fibres @jdm and @HectorLooi .  I use some dirty rodeco and bench brush down my work surface after I use it.

@Michael1962https://www.cousinsuk.com/category/fibreglass-scratch-brushes