Any bottle caps will do as long as they're clean and dry. Grab your penny or trinket, what ever you want to put in the bottle cap (make sure it will fit too!) I'm sure you can even put a picture or piece of paper in it (glue it down to the bottle cap with liquid glue, Aleens tacky glue or Mod Podge, let dry, cover the whole top with more glue with a paint brush or finger to protect the image/print)
Just place your trinket at the bottom, arranged how you want it and slowly pour in the dimensional magic evenly. DO NOT SHAKE BOTTLE, it will cause air bubbles and they're a pain to get out and they don't pop like a regular bubble would. If you do get air bubbles get something sharp like a safety pin and try to move them to the side and get them out. When you're done, make sure it's on an EVEN surface to dry or else it'll dry unevenly and the top won't be even and the dimensional magic will spill over the side.
Let it dry undisturbed for a few hours and it shouldn't be cloudy anymore, you will be able to tell if you need to add more dimensional magic to top it off or not. Let it dry over night so it's dry 100% top to bottom.
Can you tell the difference? I took these pictures today, July 9, 2013. Story time! A couple weeks ago I noticed that Chris lost his key chain (it came unglued) and he couldn't find it anywhere. A few days ago he went out to the car and saw a bottle cap upside down in the driveway. He thought it was weird because we hadn't bought the same soda bottles in a long time which is where I got the bottle caps from. He thought it could be his key chain, and picked it up and because it felt heavy he knew it was it, turned it over and he was right. He gave it to me to glue back on and told me not to make a new one because this one has a story now. It was really hot outside for about a week, like in the 90's that's why his is cloudy and...