No more twist-ties or rubber bands!
This method is WATER PROOF AND AIR TIGHT.
Cut up a disposable water bottle and keep the neck and top, as in photo.
Insert the plastic bag through the neck and screw the top to seal.
The bag is made air-tight, water will not leak, it is easy to open and the top and screw cap can be used over again!
Thanks Grumpy
Do It And How 