Whatever the trouble was that the plants encountered, we really can't recommend reusing the soil or trying to sanitize it for reuse. So many pests and diseases are perpetuated in the soil and it would be such a shame to have another generation of plants succumb to the same problem despite your efforts. 

The best advice is to dispose of the soil and to clean your pot thoroughly, first removing any soil and debris with a stiff brush and then washing with a 10% bleach/ 90% water solution, then soap and water, rinsing well.

For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service