Pianists are the only musicians who do not service their own instruments. Understandably! There are more than 12,000 parts in some pianos! Just because you may not be servicing your own instrument, I think you can know more about the inner workings so that when you want a better performance you know better how to ask for it.
First thing you’ll need to know is what the insides look like. Here’s a video demonstrating how to open one piano.
There are many different designs for pianos. It’s uncommon for me to work on one I can’t instinctively disassemble for service but it still happens. Some require a flat-head screw driver, others a phillips head. I’ve come across many which have a simple swivel catch made of either wood or metal. There may be a pin, similar to a hinge pin, pressed between two piece and is very easy to remove. Others might be rather difficult and require special tools not everyone has in their tool box – I found one which needed an Allen (Hex) key in the rear of the piano, pressed against the wall. That took a little tinkering to find.
The important portion to this is that you shouldn’t try pulling too much apart unless you’re comfortable with making the repairs or paying for someone else to repair them. Some seemingly simple mistakes can cause a lot of damage and hours of work. That being said, retrieving a pencil or paper clip doesn’t usually require much more than space for your fingers to grasp it.