White residue when stripping miniatures

[Luigi]

Sometimes, when I strip miniatures with Super Clean^TM

I end up with a miniature covered with this chalky or glazed look. It covers and obscures details.


you can see the right model is just completely covered in it. while it's dotting a few recesses on the left model.

it can be scraped of with a toothpick but it's impossible to get rid of it this way.

It happens on both plastic or pewter miniatures and it won't dissolve in water/ammonia/isopropyl alcohol/bleach/oil/vim/another bath of super clean/vinegar.

it doesn't happen all the times and it has happened in both single and mixed stripping batches, with only a few miniature developing this residue.
What is it, how do I deal with it? 

[Mindenbrush]

That is an odd one that I have not seen before. The Super Clean “tips” tutorials show that it is just rinsed in water to remove it.

When I have stripped figures using Simple Green or Nitromors paint stripper I use a soft brass bristle wire brush to lightly ‘polish’ up the surface to get rid of any oxidisation/surface contamination.

[Mammoth miniatures]

What sort of container are you stripping them in? I'm wondering if the stripper is leaching some chemical fromthe container which is being deposited on the miniatures?

[Luigi]

That is an odd one that I have not seen before. The Super Clean “tips” tutorials show that it is just rinsed in water to remove it.
When I have stripped figures using Simple Green or Nitromors paint stripper I use a soft brass bristle wire brush to lightly ‘polish’ up the surface to get rid of any oxidisation/surface contamination.

Yeah, usually do the same, and it works perfectly fine, but this time just won't subside :/

What sort of container are you stripping them in? I'm wondering if the stripper is leaching some chemical fromthe container which is being deposited on the miniatures?

usually glass jars. The container doesn't seem to be an issue as often the same container has yield mostly perfect result before getting the one odd miniature that comes off like this.
I've also had some miniatures come out like this from the same batch of other miniatures who came out fine.

[Mammoth miniatures]

Just had a look at the COSHH sheet for Super clean - It seems to be mostly sodium based so it could be that you've literally just got crystals forming on your minis if you're leaving them to soak - that'd explain why it's happening sometimes and not others and only to certain minis, once one mini starts to form a crust then it'll be that one that gets the rest of the residue.
 

[Luigi]

Just had a look at the COSHH sheet for Super clean - It seems to be mostly sodium based so it could be that you've literally just got crystals forming on your minis if you're leaving them to soak - that'd explain why it's happening sometimes and not others and only to certain minis, once one mini starts to form a crust then it'll be that one that gets the rest of the residue.

Interesting!
Now I feel like a kid playing with a chemistry set

Any idea on how to deal with sodium crystals? I'm probably going to try acetone since it's the only thing I have not tried yet.

[Mammoth miniatures]

Interesting!
Now I feel like a kid playing with a chemistry set

Any idea on how to deal with sodium crystals? I'm probably going to try acetone since it's the only thing I have not tried yet.

erm...maybe a soft metal brush? if it is sodium crystallization then maybe a soak in vinegar or a weak acid?