It is always recommended to do a patch test before the wash.
Use cold water to wash your banarasi silk saree.
Add mild detergent or shampoo to the water
Soak the saree for 5 minutes
After soaking gently rinse the saree
Never brush or rub your saree, even doing gently could make the threads of the saree spring out
Never wring your banarasi silk saree
Dry them under shade.
Saree covers or muslin bags are recommended to store your precious saree.