Both Wet Bags and Pail Liners are designed to do the same thing - store wet and soiled diapers. The differences come in the size and method of use. Both wet bags and pail liners are designed to be washed with your usual diaper laundry. Simply empty the diapers into your washing machine, then toss in any wet bags and pail liners.
Wet Bags
In short, a machine-washable Ziploc bag, and a key tool if you'll be using cloth diapers out of the house.
Design: Wet bags have a zipper or drawstring at the top, with an inside pocket made of PUL (the same waterproof fabric used for the outside of diapers). Planet Wise, Wahmies and itti bitti all add super-cute decorative fabric outers. These fabrics wash up well and, providing you do not use bleach on them nor leave them in the sun for long periods of time, will stay bold and bright for years.
Function: Simply keep your wet bag in your diaper bag or car, and stash any wet or dirty diapers inside after diaper changes.
Wondering which wet bag or bags is best for you? Check out this comparison post.
Pail Liners
In short, a machine-washable trash bag, and a great way store diapers at home.
Design: Wahmies pail liners are made from PUL (the same waterproof fabric used for the outside of diapers), and have an elasticized band at the top of the bag.
Function: Line your diaper pail with a pail liner, then add any wet or dirty diapers through the day. At laundry time, simply remove the pail liner from the pail and transport your sack (looking quite similar to Santa Claus) to the laundry room. Dump the contents into the washer, then throw in the pail liner as well.
I recommend two pail liners, so you'll always have a clean one standing by for the pail. Diaper pail? Simple kitchen trash pails work best. No need to buy the big-name diaper pails.
Blueberry Wet/Dry Bag
Planetwise Wet/Dry Bags
Planet Wise Mini Wet/Dry Bag