Those over-the-counter remedies that say "consult a physician before giving to children under 2" or perhaps even "Do not give to children under age 2" -- they mean it. The CDC has recently published a reminder of that fact. Babies are dying because parents ignore that warning.
If your infant or toddler has a cold, use a bulb syringe
or even better a nasal aspirator (easier to clean)
Saline nose drops won't hurt either -- you can buy them at the pharmacy or ask your pediatrician for a recipe. But for your baby's sake, do NOT give them medication designed for older children unless the pediatrician has given you very specific instructions about dosage and frequency. Then do NOT add other medications without the pediatrician's instructions.