diff --git a/lib/mbtiles.js b/lib/mbtiles.js
index e5f7495..220ec1e 100644
--- a/lib/mbtiles.js
+++ b/lib/mbtiles.js
@@ -566,31 +566,6 @@ MBTiles.prototype.putTile = function(z, x, y, data, callback) {
     else return callback(null);
 };
 
-// Inserts a duplicate tile into the MBTiles store. Scheme is XYZ.
-//
-// - @param {Number} z tile z coordinate
-// - @param {Number} x tile x coordinate
-// - @param {Number} y tile y coordinate
-// - @param {Number} duplicate tile ID
-// - @param {Function(err)} callback
-MBTiles.prototype.putDuplicateTile = function(z, x, y, id, callback) {
-    if (typeof callback !== 'function') throw new Error('Callback needed');
-    if (!this.open) return callback(new Error('MBTiles not yet loaded'));
-    if (!this._isWritable) return callback(new Error('MBTiles not in write mode'));
-
-    // Flip Y coordinate because MBTiles files are TMS.
-    y = (1 << z) - 1 - y;
-
-    // This corresponds to the map table.
-    var coords = hash(z, x, y);
-    if (!this._mapCache[coords]) this._mapCache[coords] = { z: z, x: x, y: y };
-    this._mapCache[coords].tile_id = id;
-
-    // Only commit when we can insert at least batchSize rows.
-    if (++this._pending >= this._batchSize) return this._commit(callback);
-    else return callback(null);
-};
-
 // Inserts a grid into the MBTiles store. Scheme is XYZ.
 //
 // - @param {Number} z grid z coordinate
@@ -642,31 +617,6 @@ MBTiles.prototype.putGrid = function(z, x, y, data, callback) {
     });
 };
 
-// Inserts a duplicate grid into the MBTiles store. Scheme is XYZ.
-//
-// - @param {Number} z grid z coordinate
-// - @param {Number} x grid x coordinate
-// - @param {Number} y grid y coordinate
-// - @param {Number} duplicate grid ID
-// - @param {Function(err)} callback
-MBTiles.prototype.putDuplicateGrid = function(z, x, y, id, callback) {
-    if (typeof callback !== 'function') throw new Error('Callback needed');
-    if (!this.open) return callback(new Error('MBTiles not yet loaded'));
-    if (!this._isWritable) return callback(new Error('MBTiles not in write mode'));
-
-    // Flip Y coordinate because MBTiles files are TMS.
-    y = (1 << z) - 1 - y;
-
-    // This corresponds to the map table.
-    var coords = hash(z, x, y);
-    if (!this._mapCache[coords]) this._mapCache[coords] = { z: z, x: x, y: y };
-    this._mapCache[coords].grid_id = id;
-
-    // Only commit when we can insert at least batchSize rows.
-    if (++this._pending >= this._batchSize) return this._commit(callback);
-    else return callback(null);
-};
-
 MBTiles.prototype.putInfo = function(data, callback) {
     if (typeof callback !== 'function') throw new Error('Callback needed');
     if (!this.open) return callback(new Error('MBTiles not yet loaded'));