I would dry it and use it for target practice only. For defensive use at home, use new ammo which has been stored cool and dry.
Gas oven or will a microwave do the trick?
Yep! Living on the shores of the Chesapeake Bay, the storm surge for 2003 hurricane Elizabeth left 4-feet of water and mud in the first floor of my house.
Some of the ammo I had stored was not on the three 20-ft-long wall shelves that were 4-6 feet off the floor where most of my ammo was stored.
Net result was that 4 cases of ammo were under water for 2-days. I tried giving the ammo to a local gunsmith. He refused it. So over a period of 6-weeks I opened all the cases (4000 rnds 7.62 and .223) and spread the ammo out on towels to dry. Most were just slightly damp.
8-years later I gave most of the ammo to my grandsons to test and use for practice. Amazingly they have had few jams or other problems in the 6-years they have been using it.