Bubbles can be caused by a variety of factors including humidity and mixing.
When you mix the Part A Resin with the Part B hardener be sure to mix it slowly, folding the parts together and scraping the sides.
Air bubbles can be caused when you use a sealant on an object or a piece of paper but do not allow the sealer to dry long enough. A bezel or found object can have surface humidity on it from the climate of the room you are working in. You can use a blow dryer on bare metal for about 20 seconds first to eliminate this kind of humidity.
ICE Resin plungers and bottle caps are airtight and as long as they are screwed on completely, will not allow humidity into the container. When working with the bottles, be sure to replace the red tops onto the nozzles to keep it airtight as you store it.