Saline Solution

https://www.webmd.com/allergies/saline-spray#1

The commercial version may be more practical as it doesn't need to be mixed on demand and is already in a ready-to-use bottle:

https://www.target.com/p/simply-saline-nasal-relief-spray-4-25-fl-oz/-/A-17263050?ref=tgt_adv_XS000000&AFID=google_pla_df&fndsrc=tgtao&CPNG=PLA_Health%2BShopping_Local&adgroup=SC_Health&LID=700000001170770pgs&network=g&device=c&location=9023315&ds_rl=1246978&ds_rl=1247077&ds_rl=1246978&gclid=Cj0KCQjw753rBRCVARIsANe3o45_dVBCgXC26deoOs3Tke1y-adX6HkhEp-6uSCwkbLZsqf9ukJOI2QaAoNpEALw_wcB&gclsrc=aw.ds