Overwrite print message in tft shield HX3856

Ive been searching for a while on how to erase the data before a new one enters. The data_values is a string variable. I tried to tft.print a null value but still the same. Any ideas on how or maybe someone did it already?

Serial.print("Voltage 1 : ");
          Serial.println(data_values[data]);
          tft.setCursor(((width_tft/10)-1)+5, 260);
          tft.print(data_values[data]);

Update : The link shows the output of my lcd shield. Also had a problem when the tft.fillRect is not updating its proper height size. Thou tested all of the drawings before completing the program

Why do you need to erase?

The new values will overwrite the old ones.

ieee488:
Why do you need to erase?

The new values will overwrite the old ones.

So this is how the data display in tft works. The tft is a slave which fetch data from the master , but everytime the data updated the tft prints looks like overlaying the data. Its not overwriting the old ones. The thing here is I know that it will overwrite but I dunno why it happens.