Install to "lxserv" directory in your script directory. Restart MODO. Use it by calling the command "ffr.deleteNamelessVMaps".

deleteNamelessVMaps.py

#!/usr/bin/env python
 
import lx
import lxifc
import lxu.command

class DeleteMaps (lxifc.Visitor):
	def __init__ (self, meshmap):
		self.meshmap = meshmap

	def vis_Evaluate (self):
		try:
			name = self.meshmap.Name ()
		except:
			name = None

		if name is None or len(name) == 0:
			try:
				self.meshmap.Remove ()
			except:
				pass

class DeleteNamelessVMaps_Cmd(lxu.command.BasicCommand):
	def __init__(self):
		lxu.command.BasicCommand.__init__ (self)
 
	def basic_ButtonName(self):
		return "Delete Nameless Vertex Maps"
 
	def cmd_Tooltip(self):
		return "Delete all nameless vertex maps"
 
	def cmd_UserName(self):
		return "Delete Nameless Vertex Maps"
 
	def cmd_Flags(self):
		return lx.symbol.fCMD_UNDO | lx.symbol.fCMD_MODEL
 
	def basic_Execute(self, msg, flags):
		layer_svc = lx.service.Layer ()
		layer_scan = lx.object.LayerScan (layer_svc.ScanAllocate (lx.symbol.f_LAYERSCAN_EDIT))
		if not layer_scan.test ():
			return

		layer_scan_count = layer_scan.Count ()
		for l in xrange (layer_scan_count):

			mesh = lx.object.Mesh (layer_scan.MeshEdit (l))
			if not mesh.test ():
				continue

			meshmap = lx.object.MeshMap (mesh.MeshMapAccessor ())
			if not meshmap.test ():
				continue

			visitor = DeleteMaps (meshmap)
			
			meshmap.Enumerate (lx.symbol.iMARK_ANY, visitor, 0)

			layer_scan.SetMeshChange (l, lx.symbol.f_MESHEDIT_MAP_OTHER | lx.symbol.f_MESHEDIT_MAP_UV | lx.symbol.f_MESHEDIT_MAP_MORPH | lx.symbol.f_MESHEDIT_MAP_CONTINUITY)

		layer_scan.Apply ()
 
lx.bless (DeleteNamelessVMaps_Cmd, "ffr.deleteNamelessVMaps")