If you're using the Gmail app to view email on your Android device:
Click the Menu button, select "Go to Labels" to see your list of labels. Scroll down until you see "SaneLater"
If you're using the Email app:
Click the Menu button, then "Folders" (or Labels) to show the list of all of your folders.
If this doesn't help, in order to successfully capture all IMAP folder changes, you must refresh from the *account list*, and not within an account itself. In other words:
Make sure you are on the "your accounts" menu.
Press "menu" button
If you still don't see SaneLater or your other folders, you're probably using POP to view your mail. You need to switch to IMAP in order to use SaneBox. Luckily, here are instructions on how to do that: http://pop2imap.com