Check that the user space is clean after checks

Have you faced a note on CRAN about non-standard things in the check directory ?

Check: for non-standard things in the check directory
Result: NOTE
    Found the following files/directories:
     ‘extrapackage’ 

Maybe you do not understand where these files came from.
Then, you can run check_clean_userspace() in your package directory to detect every files that you created during the check.
They could be issued from examples, tests or vignettes: check_clean_userspace() will tell you.

#' \dontrun{
# This runs a check of the current package
all_files <- check_clean_userspace()
all_files
#' }