To delete all files which name has xxyymm, you can use:
find . -name 'xxyymm*' -exec rm {} \;
or (with the option -f)
find . -name 'xxyymm*' -exec rm -f {} \;
Delete all files in current directory and its sub-directories where the file name starts with “foo”
find . -type f -name foo\* -exec rm {} \;