gistfile1.js

var markers = new L.FeatureGroup();

function locate_map(_lat, _lon) {
  map.setView([_lat, _lon], 18);

  var marker = L.marker([_lat, _lon], { icon: marker_icon })
  .addTo(map)
  .bindPopup("LT1")
  .update();

  markers.addLayer(marker);
  map.addLayer(markers);
  var map_hash = new L.Hash(map);
}

function removeAllMarkers(){
    map.removeLayer(markers);
}