[woodcote]

Allan - yes that can happen with the curved lane changers (which haven't been produced for ages). On the in-to-out changers, the cars' guides will be pushed towards where the end of the flipper sits and can catch. Once you get a few high-speed collisions with the end of the flipper, the delicate point gets bent and that makes it worse.

A couple of things I've learned...

• Scalextric guides should be okay. I don't remember having any issues with an undamaged flipper.
  
• Non-Scalextric cars are more problematic, depending on the guide.  Those with plenty sticking out the front (Slot.it 'Racing' guides, Scaleauto, Sloting+, Revoslot, Thunderslot etc) need the front cutting off or changed for a more standard guide (eg standard Slot.it CH10 or NSR)
  
• The Carrera guides are just way too long and it's the back that pushes the front into the flipper. I'd recommend using the BRM-126 guide blade on Carrera cars - but still reduce the width at the front and trim 5-10mm off the back if you're using curved lane changers.
  
• Sharpening the front of the guide too much makes it easier for the guide to dig out the flipper - so it's not always a solution. Reducing the width on an overly-wide guide (eg Carrera) will help.
  
• Don't place a curved lane changer (especially an in-to-out) at the end of a fast straight - it's just asking for damage.
  

I've not taken apart a curved lane changer, but I have the standard straight ones. If you do, I recommend taking a photo of each stage so you know how it goes back to together again. I'm pretty sure I didn't remove the flipper, so I can't help you there.

I presume to want to remove the flipper so you can repair damage at the tip?