walnut oil has crap at the bottom of it..

[tank8140]

i was at the supermarket and was about to buy some walnut oil to make some test prop with. Well all the bottles of the walnut oil had like this darker shit stuck to the bottom. When i shook the bottle, it swirled around, didnt go away. However, this was only one particular brand of walnut oil i looked at, but it was the only brand the store had.
Is this normal/ ok to use?

Also, a little off topic but does anyone know if filtering through a .22 filter reduces injection pain (compared to a .45 filter)?

 

[DocJ]

Should be ok, I'd filter the oil separately through a .22 micron filter before you do anything with it for sterilization.

I've never heard of a .22 micron reducing injection site pain.