If you have been on P2S for some time you will probably have accumulated a lot of email accounts. In my opinion it is best to keep track of those email accounts and which advertiser you have used them with. My method is to start up a notepad file in windows (you could also use microsoft word or some other notepad type application) and put the email address, password then the advertisers after it. Here is an example of what an entry would look like:
firstname.lastname@example.org - outrun - HRV, NDR
email addres, password, then advertisers that you have used the email address for
Since you have to have a unique email address for each offer this makes perfect sense to do especially if you plan on staying on PS2 for a long time. It may seem like a lot of work but it only takes a few seconds to note each email address and what advertisers you have already used it for. This will help so that you do not use the same email address for the same advertiser twice, which is a no-no that decreases your approvals.