Do you have a project that requires a metal can? Whether you're making a planter, a bird feeder, or something else, you'll need to know if the can will rust. For the most part, any of these styles can be used for any of these projects, though you should remember that metal cans rust if exposed to water. I had a place in my garden where every time I planted a rose it would die. My garden artist suggested that there might be an excess of iron there and suggested deep tillage and soil treatments.
On the first day of digging, we found a rusty horseshoe that was killing the roses. When selecting a metal can for your project, choose one that does not contain rust. Although some rust can be cleaned from the can before painting and sealing, watch for stubborn stains or grease residue inside or outside the can and on all edges and seams. Choose a cleaner can for best results. Iron rust is unlikely to be a problem for plants. Oxidation will accelerate with plants, so it is possible that the containers will fall apart after a short period of time if the metal is thin or is already mostly oxidized. If you plan to paint your metal can, be sure to order a non-toxic paint.