You may try removing that spot if you can. If it's just some food that has stuck on your tooth, you should see a clear smooth part of your tooth afterwards. By the way, removing food sticking on our teeth will be easy.
If it appears that after scraping a portion, there still is a cavitation or discoloration, you have tooth decay over there. But if you find yourself continuously scraping without any tooth part being detached and the black spot remains as it is, you have an arrested caries. You should not worry of arrested caries since your body has found its way to control the disease.
If you prefer to have the tooth cleaned out, you may. But if it's just a small cavitation and you are optimally healthy and your diet is excellent, your body can do the work and heal and remineralize the decay.
A little more about the book: Forget about drilling, filling, and the inevitable billing. Your teeth can heal naturally because they were never designed to decay in the first place! They were designed to remain strong and healthy for your entire life. But the false promises of conventional dentistry have led us down the wrong path, leading to invasive surgical treatments that include fillings, crowns, root canals and dental implants.