Checking spam "To" field w/o ping-back

I have several email addresses that resolve to the same inbox. I want to check which address is getting spammed, but don't want to confirm for the spammer that the address they sent to is valid by opening the email.

Is there a way to see the address in the "To" field without opening the spam or otherwise triggering a surreptitious send-back to the spammer? For example, if I click "Forward" without explictly opening the email, it allows me to see the message, including the To field. But even though the spam wasn't explicitly opened, will any feedback loop to the spammer still be triggered? Alternatively, if I go offline prior to this action (or similar), and delete the spam prior to going back online, will that bypass any feedback loop?

Thanks.