[Konstantinos]

pawn Code:

// A single 3D label:
native DestroyDynamic3DTextLabel(Text3D:id);
// You should store the ID for the 3D label in a variable so you can check whether it's valid, delete/update it or get the text later on

pawn Code:

// All of them:
native DestroyAllDynamic3DTextLabels();