You can only take a tax deduction for specific types of donations. If you have donated products or services do the following:
- Create a Products and Services Item named "Donations" and create a Donations Expense Account (Charitable Contributions Type), then map the Item Income Account to this Expense Account.
- Then create a Sales Receipt and enter the the products or services being donated at their original price, then add the "Donations" line Item you just created and enter a negative number to zero out the receipt amount.
This provide you with an audit trail for the donation and record the donation expense at the same time.