It used to be that the bottle caps on top of plastic juice, milk and water bottles had to be removed and discarded before placing the bottle into the recycling bin. The reason? The plastic caps are a different type of resin (a No. 5 plastic), which is different than the more commonly recycled No. 1 and No. 2-marked plastic bottles. But today's modern recycling technology has made removing the cap obsolete. The bottles and caps are ground up and flaked; when the flakes are placed in water, the Nos. 1 and 2 plastic resins sink, and the No. 5 plastic floats, which makes separation a breeze.