There’s a slight difference between adding funds collected offline to a regular tilt and adding funds collected offline to a nonprofit tilt—but both are totally possible.
For regular tilts:
Simply add up the amount of cash and checks collected and deposit the total into your bank account (or set it aside to use when the time comes). Then make an organizer contribution to the tilt for that amount from your own account by clicking the 'Contribute' or 'Pay' button on the tilt page. You won’t actually get charged for this amount, but it will show up in the total collected. The organizer contribution will be subtracted from your final payout. (Since it’s already in your pocket, get it?)
For nonprofit tilts:
If you are running a tilt benefitting a nonprofit organization, you have two options. First, you can lower the tilt amount by the amount of the checks you collected offline—and send the checks via physical mail to the nonprofit. Or, you can reach out to the Tilter Happiness team using the link below to add the funds collected as "offline contributions." These will act as placeholders and count towards your Tilt amount.