Doug uses glass vials, so glass must be ok. <br><br>Have we ever determined if the little metal containers that a person at risk of a heart attack would carry with nitroglycerin inside is okay for PotableAqua tablets? I understand nitro tabs are relatively corrosive as well. So, maybe, these specialized containers would do for the PotaAqua as well?<br><br>Thank you, Xavier Phx, AZ