Email/zip submit scrub a lot, how you deal with that?
Check on offervault to see if any other networks have the same one and rotate them. Also keep testing new submits that match your target audience.
multiple accounts help too.
Rotation is the best legit method.
You can also send really good quality traffic depending on your campaign, and tell your manager to talk to the advertiser and adjust your account based on your quality (I've never done this with submits, and some networks may take offence, but it's just how it is)
Ask the network to "right price" your traffic. You may be in for a pleasant surprise 

Suggest to users to complete more than just the email submit in your adcopy; it works. If you're EWA, we have other solutons too that help keep it high.
@ bluaffiliate: Whats up the the USELESS post? Thumbs down for you.
Like Jordan said, search for the same offer on multiple networks and trow them in rotation. thats what i do
probably a noob question but how exactly is the scrub applied? I was running an email submit and after about 15 conversions the CR tanked. I'm guessing they simply don't count later submits to compensate?? Is there any way to anticipate exactly how this will affect the campaign or should you just rotate and move on? Then, is there ever a point where you can rotate an offer back in, or is it pretty much 'used up'.
I think it is better to encourage people to actually complete the rest of the offer as it will make everyone happy, but does simply suggesting it really have an effect? I would think that any more aggressive approach would hurt the campaign.
make it work with the scrub