It's pretty simple
Make a excel file, click on "Data" -> From web -> Insert
http://altexplorer.net/address/ (your wallet address here) and select block that shows transaction and balance (you need to click on small yellow arrow icon on left side.) and then click on import.
Do this with all your altcoin address and collect all data on same page, for eg:
Then right click on each block and click on "Data Rage Properties" and check "Refresh data when opening the file" option.
Once you add your all wallets data, open Sheet 2 and make a small summary.
For example:
To grab balance from previously created data click type = and select first cell that shows balance. Eg: 14.2125 COYE
You can then add a total count if you want or you can also grab current prices from various exchange sites and calculate total value of your coins in USD/BTC
Ps: I didn't tested this but I think when any new transaction will come into any address, that last balance transaction will get replaced by new one.
