We received the tip that when you want to sand molding, you can make a custom sanding block by wrapping thin plastic wrap over the molding and then forming a block into the wood molding with epoxy auto body repair putty. When it hardens, remove the block, pull off the plastic and you have a pretty good duplication of the molding.
Now you can use rubber cement in a bottle or a spray to attach sandpaper to the block.
When we tried it we found that it did a pretty good job for the larger surfaces, flat or curved, but didn't get into the detail very well.
A look at the third photo shows you the commercial profile sanders that are available with a wide variety of different shapes for sanding heads and self adhesive sandpaper. The same idea as the molded block, but one part of the shape at a time. FEIN Power Tools has just released the "Profile Kit" which has all sorts of sanding profile attachments for the FEIN MultiMaster.