I think they've baffled most of us the first time we have encountered them and can be a bit of a battle to remove if you can't figure them out!
It's important to get all your hardware off at the start of any job though and so this is my go-to method and the tools I use for getting them off easily 
Let me know what you think and if there are any other tips you'd find useful!
Nicky x
If you want to see more of my favourite tools - none of which cost the earth! - check ot my Top Ten Essential Tools for Upcycling blog post:
https://doneupnorth.com/blogs/latest-posts/top-ten-upcycling-tools
If you want to learn more techniques for upcycling and more about using the tools themselves why not take a look at my Furniture Upcycling workshops? I also do one-to-one tutorials in person and online if you'd like to learn something specific with me!