Cleaning Terra Cotta

How do I clean old containers so new plants are safe from disease? Both clay and plastic. Thank you.

To clean your containers soak them in a 10 percent bleach solution for about thirty minutes. This will kill any pathogens and prevent passing disease from one planting season to the next. Smaller sized containers can be put directly in the dishwasher for sterilization. The discoloration on some terra cotta pots is caused by salt build up from fertilizer. These salt rings can be cleaned off with a paste of baking soda and a little water.