If you are worried about your credit score, you could adopt the following strategy: choose one monthly expense per card. For example, dedicate a card to groceries and charge all your groceries, and only your groceries, to that card and then pay it off completely at the end of the billing cycle. I use this to keep my accounts "active" without paying any interest. For example, you could have a card specifically for
-groceries
-gas
-cell phone
-internet
-insurance payments (or split car/home/renters/health/life/whatever else over different cards)
-etc
The only issues might be if the company in question, say your internet provider, charges you a fee to pay by credit card. Obviously you do not want to be paying extra money if don't have to. I personally don't have as many credit cards as I do bills so I double/triple up on some cards. The main point is that you pay them off COMPLETELY every month. If you cannot commit to doing this, then just lock/cut the cards up but keep the accounts open.
Also, if any of the cards are rewards cards you will want to put your biggest monthly expenses on the cards with the best rewards programs. Good work paying off the first seven, and keep up the good work until all are paid off!