> Boil a bottle of water and you can pop the lid off it without breaking the seal, keep that in boiling water, refill the bottle with what you want, take the lid out and push it back over, when its cooled it looks like new.

Make sure to label it "saline solution" and claim it as a medically necessary fluid (or any of the other numerous exempt fluids and gels) so that you can go over the 3.4fl oz limit. Hell, just call it your "enema solution". What TSA agent would look too closely at that?