Remember when Biden just plain didn't nominate someone to the board?
It's not as accurate as mass spec but generally speaking you can test for geavy metals using certain acid and color changing indicators (in known concentrations) over a range of sample dilutions. Even better if you have a reference sample of a known concentration of the target, like manganese. Sometimes the chemical is not itself an acid but nevertheless reacts with the target.
For example, high concentrations of manganese will react with peeiodate to make a red/broan color. You can buy a set of 100 pouches of periodate for manganese testing on Amazon for $50.
Without being greedy
Costco has the same profit onus of every other company it just uses a slightly different business model that means ita members get huge volumes of cheap goods. That's it.
It is exactly as greedy as every company anykne dislikes. The oppression of capitalism is not due to greed, it is a built-in mechanism that profits must be maximized. It doea not matter how highly a business owner or customers think of the company, it is a profit-generating machine or it will die.
Example: Costco always fights the union.