After you file

If you already included the income on your 2017 return, don't include it in 2018.

If you received a 1099-MISC form just keep it in your files.  If you happen to get a letter from the IRS down the road asking why it wasn't included on your 2018 return, just explain that it was included in 2017.

If you've already enter the 1099-MISC, you can delete it using these steps:

TurboTax Online

1. While in your return, click on Tax Tools > Tools (in the black bar at the side of your screen).  
2. In the Tools Center, under Other helpful links click on Delete a form.
3. Click Delete next to the form you want to delete and follow the onscreen instructions. 
4. Once you have finished deleting the desired form(s) click the Continue with My Return box (in the lower right of your screen).

TurboTax CD/Download

1. Go into Forms Mode by clicking on the Forms icon in the top right of the blue bar. 
2. In the Forms in My Return list on the left, click on the form you wish to open and delete.
3. Click on the Delete Form box at the bottom of the screen.
4. To return to the interview, click on the Step-By-Step icon in the top right of the blue bar.