Beethoven is notorious for his atrocious musical handwriting. I feel sorry for his copyists. No doubt he could have saved some broken families if he'd had access to Finale back then. Even now that we have sound recordings of all his music, it is still no easy task to follow his scores. Nonetheless they are fascinating to look at for many reasons, not least of which is to show how much care went into his compositions. His manuscript scores are riddled with cross-outs and corrections, yet these are supposed to be "final drafts". For example here is arguably his greatest composition, the 9th Symphony (Ode to Joy, etc...). Riddled!
1st Movement Page 1, and some others:
2nd Movement Page 1:
3rd Movement Page 1:
4th Movement Page 1:
Whew. Kind of like the tablets the 10 Commandments were written on for a Beethoven fan like me... You can see the ENTIRE 9th Symphony autograph manuscript at the below link from the Staatsbibliothek zu Berlin (where the above pages are from).