Supplies:
ModPodge
Paint Brushes
Various Colors of Glitter
Clean dry empty jars
Paint a design(stripes, heart, letters, polka dots) on inside of jar with ModPodge and then pour a bit of glitter inside and roll around to cover your design. Tap the jar upside down onto a plate a few times to remove excess glitter.
To use multiple colors on one jar, let the first color dry completely before adding the next color, this keeps them from mixing.
After you have finished the designs and glue has dried, coat the entire inside of jar with a thick layer of ModPodge and allow to dry for at least 24 hours. This will form a seal over the glitter to help with flaking(although you may still get a little).
Here is a picture of the finished project: