The things you are talking about are called "floaters". They are bits of cells that remain in the vitreous humor after birth and float around when the vitreous becomes more liquified later in life.
They break into little pieces that forever float around in your eye, and sometimes you will be able to see them. There is no way to get rid of it (to my knowledge), and there is nothing to worry about
![Smilie](/tfp/images/smilies/smile.gif)
. I notice them every so often too.
Here is a picture of what you are talking about if I am not mistaken:
Hope that helps.