use strict;

use File::Find;

my @files;

# First we fill @files with the (full) path of
# all files in the directory
find( sub { push @files, $File::Find::name }, "/usr/home/foo/files/" );

# Now we check each file if it  has become too old
foreach (@files) {
  # If our file is older than one day, we will (try to) delete it
  if (-M > 1) {
    unlink $_;    # no error checking here ...
  };
};

... The rest of your script goes here ...