Some scripts are persisting even after being deleted. Try this on the object first to see if it will shut the script down.
default
{
state_entry()
{
llSetSitText( "" );
llSetTouchText( "" );
llParticleSystem( [ ] );
llSetText( "", ZERO_VECTOR, 1.0 );
llSetTextureAnim( FALSE , ALL_SIDES, 1, 1, 0, 0, 0.0 );
llStopSound();
llOwnerSay("This Prim is Clean... ");
llRemoveInventory( llGetScriptName() ); // vanish without a trace...
}
}