Which brands are contaminated?

[Pittsdriverwes]

I really like the videos that this guys does and this one is a pretty interesting take on how clean the manufacturing process is for many different brands:

https://youtu.be/9GAUo8eUXeU

An interesting surprise at the top of the list of cleanliness.

[justjoe]

I'd like to see an actual study with thousands of samples. That said, this test was very interesting.