No offense but why don't you memorize the songs by singing them instead? I memorized hundreds of songs just by being a dad and singing to my kids every evening. Of all the things you'd want to remember, song lyrics look to me to be the easiest by far.
I guess it matters how long it is and if you need to know it exactly, and how long you need to retain it. I had to memorize 50 to 100 word phrases and I chained them together with index cards. The first sentence is the cue for the second, the second for the third, etc. Carried them around in my pocket in order and started from first a few times a day until I could do the whole thing. But I only needed to know it exactly for a few weeks usually.
I've gotten tremendous mileage out of exporting book highlights to BufferApp.com and setting them to release only once per day or so. Shuffled, they pop up days, weeks, months after I've put down the book, re-igniting its themes as they spark discussion.
