My "original" Lionel 4-4-2 starter set (2004 Pennsylvania Flyer the set that got me back into Lionel/O Gauge trains for Christmas that year) engine is at my dealer being "restored". I'm incredibly excited to get it back and running again. Meanwhile, I've got the cars - a gondola, boxcar, and caboose here at home and wanting to really clean them up to look like new. Anyone have any good suggestions on how to go about this so I don't damage the paint and finish? They are the basic plastic cars with plastic trucks and couplers. Dusting with a brush only went so far. Would appreciate dos and don'ts. Thanks!