Yeah this is something I do frequently. I discovered it while studying for my qualifying exam. When I first took the exam, I failed using the same study methods I used in undergrad. I realized the scope of information I had to know was much too broad to be able cram or understand through past homework problems. So as I went through my study materials I wrote down the material after reading in designated sections, keeping the summaries to just one page. Then during further review I used these pages of notes. The second time I took the exam I got 100%.
When I would study for exams, I found the process of writing notes would be almost more useful than the process of reviewing them. The process of writing notes made me boil the concepts down into more discrete forms, and the physical action of writing helped with the memorization. A few days before an exam, I would often find myself re-reading my old notes and condensing them down into briefer notes, eliminating full explanations of concepts in favor of keywords or mental links to the full note sets.
The net result was that when I was in my exams, I would find myself mentally looking at my notes, and finding a formula or something would just be a matter of 'reading' them.
