I have no idea how to scrap the sheet, but I would be willing to participate in the mass reaching out to the bounty participants (at least the ones that participated in "bigger" campaigns such as signatures and translations)...
I don't have the time yet to check it correctly but I think there is a permission link needed from the author of the spreadsheet to do this. I tried to do something but there is no way without permission from the creator, even if you download this spreadsheet. The only way to do something is to manually add all usernames from spreadsheet to PM.
I think to inform only signature campaign participants would be enough to spread the word because it is 900 members. A lot of work, so if you want to help, then we have start to do it right now because only 3 days left.
Did you perhaps already made a template? Also is this mass PM sending allowed here or are they any restrictions? Just to be sure so I wont make any silly mistakes and receive a warning or even something worse.
ps. I will be sending notifications to translators, those will probably be the most eager to file claims as they "earned" the most. And stakes for the sig campaign are not complete (only stakes for bonus activity and special bounty are entered), so I am not sure how those participants will be able convincingly present their "case".
edit: done, I have sent a reminder to all translators, most of them have been last active on Bitcointalk months ago, some years ago, so we shall see.