Can you remove the solder? Yeah I'm sure you can scrape it off or use some desoldering methods. I don't really see the reason to care. It wont void your warrenty. You didn't actually mod anything internally if you're using the contact points. It's the official way to wireless charge it (just not paying the official price).
So you are saying that soldering the contacts on the back of your wireless phone doesn't void your warranty? ... You're kidding ... Right?