Food Safe Info Request Please

Hello, I recently picked up these small pots. I thought they might be salt cellars, but then I started to wonder about how to know if pieces are food safe, especially when their original purpose is not clear. Is there any way to tell if pieces like this are OK to use for food? Thank you :)

You will sometimes see pieces of decorative pottery that may have a label that says they are not food safe, it is likely that in the majority of cases the manufacturer is just 'covering their ar** ' as they haven't gone to the expense and bother of having a piece officially tested to whatever the appropriate std is for a retail item. A normal glaze fired at high temp should surely be food safe as it should be chemically unreactive with all but the most aggressive chemicals. Any problems are where the glaze is flaking or damaged and likely to come away and be ingested, then it may depend on what chemical elements are in the glaze. The problem elements - and then they would probably have to be in soluble form - would include things such as barium, cadmium, chromium. I used to be a paint chemist but that was a while ago so I am only offering my thoughts but there is probably a much more definitive answer out there - somewhere.

wash everything well as you don't know what has been put in it !!

Thank you all very much for you replies. I find lots of things I think would great fruit bowls and then stop and wonder if it's safe - so this is all really helpful! Interesting to know the not for food use labels are often because they've just not been tested, also I didn't know that about Raku. Yes, always give it a good wash - never know what someone's used it for :)

Poisonous Lead glazes are common in older domestic pottery, made before we fully realise to damage they do. Very much so in earthenware.
An interesting link
https://www.lakesidepottery.com/HTML%20Text/Tips/About-lead-in-pottery-or-ceramic.htm

Does not mention finished colour? Is not medieval pottery green if it contains lead? Can it be in other colours?

Thank you for the link Philpot, that's an interesting read. Also interesting about Raku, I watched the Pottery Throwdown Raku episode last night, never realised when watching in the past all the lovely Raku bits they made were more or less display pieces.

I did wonder about this dish of mine, believe it's quite old and so never sure whether it should be used...
https://www.20thcenturyforum.com/t27986-dish-made-in-france-with-bird-mark-ccf-cigogne#197378

I've also read that matt glazes aren't particularly food safe and with the broken bubbles on the attached piece I've aired on the side of caution...