This should probably go in the tips and tricks section but pure lemon juice will eat away at steel but not touch brass! This would be very useful if you could find a way to use it but to be safe I would just try a few squirts of wd40 to start with. Some of those adjusters are pushed on quite tight and if they have never been off could explain why they are being such a problem. I agree this is not the easiest thing to start with but I know what its like when you are itching to get going 
An ideal clock to start with would be anything with just one keyhole that tells the time only. You would have just one train of gears to deal with and even some of these alarms can be a little tricky to get back together. Please dont do what I did when I first started, I just kept taking clocks to pieces until I came to one I could fix and also could remember how to get it back together. I had about twelve clocks in boxes knocking around the place as well as their cases. Not an ideal situation when you dont have a large amount of room.
