I would not spray into the camera – you could get solvent or DeoxIT® into areas where you do NOT want. If the batteries are in a portable charger with corrosion, you could use the D5 there.
The DeoxIT® will clean and improve electrical connections (battery connector terminals, plugs/sockets, memory card connections, etc.).
Either use our DeoxIT® D100L-2DB or similar 100% applicator or spray the D5 (or other DeoxIT spray) onto a lint-free swab and dabbed the connections. if there is severe corrosion, you may want to use one of our brushes (Part No. AB-25). Depending on how much corrosion is present, you may need to apply, brush and clean a few times. Once clean, leave a small layer of DeoxIT on the surfaces.