Compass shows direction inaccurately, what to do?

Smartphone is exposed to various magnetized objects ( magnet phone covers) and sometimes the compass is not working properly. Its recommended calibrate to compass time to time .

To do that open Huntloc compass view (button is on the left bottom corner in map view). To calibrate the compass  there are a number of possibilities (see also https://www.youtube.com/watch?v=k1EPbAapaeI):

1. Draw each of the three sides of the device in the air three times the number “8”;
2. Turn the device on three sides, three times around its own axis;
3. Run the device in the air three times the number 8 shape as shown.