Is it safe to grow herbs and vegetables in old tins / cans?

Do corrosion and rust leech anything in the soil?

Tin and tinplated cans sometimes leech tin into the food inside them.

- http://en.wikipedia.org/wiki/Tin_can#Dissolution_of_the_tin_coating_into_the_food

They are frequently now lined with coating on the inside to prevent this leeching. Ironically the coating also leeches into the food.

- http://www.telegraph.co.uk/health/2969039/Chemical-in-food-tins-doubles-the-risk-of-heart-disease-and-diabetes.html

- http://www.choice.com.au/reviews-and-tests/food-and-health/food-and-drink/safety/bpa-in-canned-foods.aspx

I ask because I save the large-ish tins I open to use as pots.

I try to only save the unlined tins, (I think you can tell by the colour inside?)

But what about the metal itself?

Metals can be very toxic. Tin is toxic in high amounts.

If I plant food in them, will the plants absorb any of the metals over time?

What about as the tinplate corrodes and the steel underneath rusts?