Line 6 is for Other Income.
If you didn't have
- amounts from finance
reserve income,
- scrap sales,
- bad debts
you recovered,
- interest (such as on notes
and accounts receivable),
- state gasoline
or fuel tax refunds you received in 2017,
- any amount of credit for biofuel claimed
on line 2 of Form 6478,
- any amount of
credit for biodiesel and renewable diesel
fuels claimed on line 8 of Form 8864,
- credit for federal tax paid on fuels
claimed on your 2016 Form 1040,
- prizes
and awards related to your trade or business,
and
- other kinds of miscellaneous
business income,
then line 6 may be depreciation recapture. If you've taken depreciation for listed property in previous years and business use has dropped below 50%, then the recapture amount is figured on page 2 of Form 4797 and added back into income.
If neither of these fit your business, post back to this thread.