Sainsmart metal filament polishable?

[nzhu]

Recently, I bought some Bronzefill made by esun from microcenter.
After my print, I took some stand paper to it only to find that it revealed a grey colored pla under the surface which means that it's not real bronze.
I thought, maybe it's too abrasive so I used a polishing dremel bit and the same thing happens. Also, I was suspiscious immediately after picking up my print since it didn't have any additional weight to it than normal pla.

So now I'm suspiscious of these chinese companies.

I came across Sainsmart metallic filament. They are making some nice sounding claims.
http://www.sainsmart.com/sainsmart-r...kg-1-1lbs.html

They say it contains 40% metal AND they say it can be GRINDED and POLISHED (I assume it means I could sand it?)

Can anyone confirm this? 25 dollars + free shipping seems suspisciously cheap compared to some other companies like colorfabb.
There's not much info on youtube or google. There's a few amazon reviews but not much. There's too many cases of the seller planting fake reviews for these to be trustworthy.

[curious aardvark]

check the weight - some companies sell smaller spools so it just looks cheaper.

[nzhu]

They usually sell metallic filament in spools of 0.5kg/1.1 pounds but it's difficult to tell by the thumbnails of the volume since
it's density that I need to tell if they're telling the truth about how much metal is in there.