Here is some common places you can find some junk to remove:

find /backup/cpbackup/daily -name core.* -exec rm {} \;
find /backup/cpbackup/daily -name *.*.mbox:2, -exec rm {} \;
find /backup/cpbackup/daily -name *.msg” -exec rm {} \;
find /backup/cpbackup/daily -name *.msg” -exec rm {} \;
find /backup/cpbackup/daily/ -name *.*.dwhs1234.dwhs.net:2, -exec rm {} \;
find /backup/cpbackup/daily/ -name *.*.dwhs1234.dwhs.net:2,* -exec rm {} \;

Basically .core files are error dumps data files and the rest are emails.