QUOTE(lifeless_creature @ Jul 23 2014, 05:16 PM)
Osren Malaysia carries the same design brush with much cheaper price than Autoglym I guess since Autoglym is so luxury branded.
Osren one has two type, Part Brush and Lug Nut Brush.
I have both.
Part Brush is very stiff. You will not want to use it for car paint surface. Use it for engine cleaning or undercarriage cleaning is ok.
Lug Nut Brush is softer but that does not mean I feel it is 100% safe also for car paint. I personally do not use it to clean item like chrome part or some tight area of the car paint surfaces. I only use it as its name indicates, wheel lug nut brushing, and it did a good job in this.
Having own so many kind of brushes, I have manage to come to a few conclusions that I think are useful to other to-be-buyer:
1) Any brush will do as long as bristle soft enough and component of the brush does not contain material that poses scratch hazard to car paint.
2) That says, if you go to normal hardware shop, get those natural animal furs wall paint brush (or nylon, but i think animal furs are softer), use pvc tape or PlastiDIP to cover the metal part that hold the bristles, then you have a safe and cheap brush to use.
Just compare the two:


The only dominant difference is the Sonax brush has the metal covered by plastic, where as the normal wall paint brush has its metal expose, but we can easily cover it ourselves with tape or PlastiDIP.

3) As for long length kind of brush (like bottle brush) which you intended to use for spoke wheel cleaning, the problem is with the center metal that holds the bristles, this one has no way to cover with soft material after it is manufactured. So you got to resort to buying dedicated automotive brush. This should be the most expensive brush you will ever need.
As for how soft is considered safe enough for car paint use, you will have to trial and error to know it. I do not know how to describe it in words.
One of the way will be, buy only one professional automotive dedicated brush, feel its softness, then next time you know what kind of softness you should be looking for.
If you ever visited shop that sells Chinese calligraphy brushes or arts tool shop, you will too find a lot of super soft, animal furs brush. But being made for art, these things are as expensive as those dedicated automotive brushes.
This post has been edited by scoutfai: Jul 24 2014, 12:33 PM