You can use this app, too https://www.willus.com/k2pdfopt/ https://www.willus.com/k2pdfopt/ to pre-process them in various ways so they are actually readable

You can use this app, too https://www.willus.com/k2pdfopt/ https://www.willus.com/k2pdfopt/ to pre-process them in various ways so they are actually readable on a Kindle. (Crop whitespace, flip to landscape etc)