Many people don’t realize that clay pots are porous. As a result salts that naturally occur in our water or in our fertilizer often end up getting deposited in the interior and exterior of clay pots. Over time they can accumulate and may even burn the roots.
To get rid of these salt deposits on the pot, soak it in some vinegar water (1/3 vinegar to 2/3 water) for at least an hour or more, then rinse the pot thoroughly. Also try using a steel brush to scrub off the salts. Then you can re-use the pot with no worries of burning the roots.