What Non-Fish Store Stuff Can Be Used In A Fish Tank?

[gale]

I've seen people use terra cotta pots, mason jars, etc. Are there any to avoid? Any tips on making them aquarium safe? I have some vintage mason jars that would look nice in a tank but I bought them at flea markets and places like that. Is just washing well enough? 

 

[Mark Z.]

I'd sterilize them in boiling water. I don't see where they would be a problem.
 
You could stand them up and put plants in them!
 
Mark

 

[Lateral Line]

Ceramics are generally safe if not too sharp edged, glass also, same corrolary. Some metals are okay in small amounts, iron for example, (it will rust, but dissolved iron in reasonable quantities is beneficial to plant growth), and precious metals if that is too your budget. Many plastics are inert. Most woods from deciduous trees if well soaked before hand. You do not need to get these things from a fish shop.