I do it...and know it's still effective b/c it's stopped hives-in-progress (from a sun rash, bug bites, etc.)
I use Nalgene brand 1-2oz containers, leak-proof, BPA free.
That being said - they are see-thru so I don't leave them out for sunlight to interact with. I've noticed the glass bottles are always colored dark.
Ask the pharmacist where you go --- they'll give you the straight deal.
Adrienne