Have large dry socket, getting repacked by dentist every other day. what kind of mouth wash can i use if any? sal water? hydrogen peroxide ok?

No need..: There is no need to use any mouthwash to rinse that area. You may disturb the packing that is in place. If the packing is dislodged, then pain will result. Hold off on any mouthwash until that area heals. Gently brush your remaining teeth and gently spit out and rinse with water.

Avoid disturbance: The goal in treating a true dry socket is to manage infection and pain while the body slowly heals. Gentle rinsing with warm salt water primarily to keep food from impacting into the socket is generally ok but vigorous irrigation will further delay healing. Avoid chemicals like peroxide or alcohol and be patient while following carefully the instruction and meds you are getting from your dentist.