Decoden Sundae Glasses

[lolita_laura]

Hey guys, I'm thinking about getting some clear plastic sundae-style cups and glasses to make cute decoden necklaces but i was just wondering, what do people use to fill them with what looks like pudding and/or jello? How do you get the opaque look for pudding or cream and the translucent look for jello?

Thanks, hope people can answer my question! :3