When you remove a file from the repository, CVS puts it into the attic. Each directory in the repository has a subdirectory called Attic. You can't check the Attic out into your sandbox, but you can examine its contents through a web interface to CVS.
To delete a file (say, phoenix.c):
rm phoenix.c
cvs remove phoenix.c
or:
cvs rm phoenix.c
If you later need to restore the file:
cvs log phoenix.c | less
cvs checkout -r 1.3 my_project/phoenix.c
or:
cvs get -r 1.3 my_project/phoenix.c
The -r option sets a sticky tag.
mv phoenix.c save_phoenix.c cvs update -A
mv save_phoenix.c phoenix.c cvs add phoenix.c