What is the preferred handling of a ketubah following a divorce? It seems wrong to just throw it away. Should it be buried? Is it permissible to burn it?
The document itself is given to the husband to prove that he actually paid the כתובה. He can dispose of it however he desires. Or alternatively, she gives him a שובר (a receipt) documenting that he actually paid her, and she can do with the כתובה whatever she pleases.
The ketubah is merely a prenuptial agreement and once the husband has paid what he promised it is an expired document which the husband can throw away or burn.