trying to decipher the code on ceramic capacitors

[renkg4bas]

Hello everyone,
I've been having a heck of a time trying to decipher the code on an assortment of capacitors I purchased from Radio Shack for a Regen receiver I'm homebrewing here at the house.

Not sure where to start....

I know that the first two numbers are the value and the third number is the multiplier, but what do I do when they only have 1 or 2 numbers printed on them?

Secondly and more importantly, how do I convert from picfarads to microfarads. I tried using a convert program I found on the internet, but the results just don't seem right at all.
 
The numbers printed on the caps I have are as follows:
1
7
10
15
68
103
151
221
561 Ceramic 
561 Blue plastic

I know the numbers translate into picofarads (at least I think they do), but again I'm not sure how to convert to microfarads.

If anyone could help me with this I would very much appreciate it.
Thank you and hope to see you all soon,
Ren
KG4BAS