Separating old 2 x 4 brick with wheel holder I am wondering if anyone knows of a way to separate the clear bottom piece from the brick on part# 7049b "Brick, Modified 2 x 4 with Wheels Holder Old and Trans-Clear Bottom" without breaking anything.  Photo for reference:  

  

I have one that has a loose bottom and it got me wondering if they could be separated without breaking them. Some of the ones I have are kinda nasty inside, while others have loose tubes that don't retain the axles very well anymore.  It would be nice if I could take them apart for cleaning and repairs, but most of them seemed "glued" together very well.  I realize they aren't meant to be taken apart, but wondered if some process including heat or something would work.  Has anyone ever tried this?  If so could you please share you experience?
I actually have one of these that comes apart easily (no idea where the internal tubes are).



It appears that the glue that used to hold them together gave out. You can still see where it used to be, around the edges of the clear piece, and at the tips of the 4 prongs on the clear piece.





If I were going to try to take one apart, I would probably try cutting the glue around the edge with a razor blade, and hope that the glue further in isn't strong enough to prevent pushing it out with a paperclip of something thought the axle holes.