Coins spawn once

Is there a way to make it so that these coins (currently just objects) only appear once. Currently I have it set up so that if the player collides with them, they get deleted, however when I leave the scene and come back they respawn.

Additional issue: I have an issue that occurs when i go back and forth between scenes. When I go from scene 1 to scene 2 and collect coins, I have a coin counter that increases as the coins get collected. However, when I go back to scene 1 it resets. If I return to scene 2 and collect more coins, the counter picks up from the number it left off on. For example: If I collect 5 coins in scene 2, go back to scene 1, it will say I have zero (I have made coin counter a global variable), i return to scene 2 and collect 3 more coins and it says I have 8.