[ShiShiLeo]

Yeah chiming in to say be careful of Tamiya panel line accent. The stuff is magical but it can indeed eat through plastic or make it brittle. I have a few kits have fallen apart or broke from it.

Edit: just saw your reply. It weakens plastic over time. You won't notice it right away. You basically want to keep it away from joints, or surfaces where it can seep into cracks and out of sight or between parts. It's ideal for parts where the detailed areas are self contained. If you're wanting to use it on an area made of multiple parts, apply the liner before you assemble the pieces. And make sure they are dry.