First and foremost. These keys on the OP-1 are delicate, but not cheap. Be careful with them, but do not be afraid to use a little force to remove them.

Next we have to make a proper tool to make removing them safe and easy

I tried a few different versions, the first ones being plastic and nothing succeeded as well as a classic metal spudger with a slight modification

Simply bend the triangular tip in about 75 degrees. This will help get underneath the keys to release the tabs.