There's also other highly technical specially-designed things out there you can use too...
Usually called 10mm sockets or 10mm spanners. They can sometimes be called 10mm ratchets or 10mm wrenches. Sometimes they're even adjustable
right thru varying sizes.
Directions for use: nicely loosen-up the row of camcaps to to pop out your required shim...
Warning: Be sure to tighten the camcaps back up again before starting the engine.