Yes, using Windex is a great way of putting Monokote over either Ultracoat or Monokote. The ammonia in the Windex activates the adhesive in the Monokote and lets you apply it with no heat.

Here is a pretty good thread that describes how to do this method.

[link=http://www.rcuniverse.com/forum/m_603331/anchors_603331/mpage_1/key_flag/anchor/tm.htm#603331]Applying monokote graphics with windex.[/link]

Ken