Just exchange them daily (couple batches a day) then the amount of real currency received is the revenue of your gross sales.

Bitcoins are a personal property their exchange a barter -- they are not real currency.

If you hold them they are investment income gain/loss like any other personal property. ( Ordinary income/loss or capital gain/loss).

Get real advice from a CPA (offered in conversation only) (If you can find one to advise on this conversion and taxation topic (doubt that)).