xbox names

I have what may be a dumb question.

We have one main gold membership on our xbox that we use for all of our games, but i created another sub account for when we play multi player, etc. and I was wondering if there was a way to delete that account or any account for that matter on there?

I want to keep the one with the gold membership, obviously.. but i dont want the one we made just for a second account...

i'm guessing that you made a silver membership account so you can only play online multiplayer, but then you found out that it doesn't let you, right?

if thats so, just simply go to the option blade thing and click on xbox options (or somthing like that) and go to memory and delete the account of your 360