Use the `-f` option. It will silently ignore nonexistent files.
From `man rm`:
-f, --force
ignore nonexistent files and arguments, never prompt
[The "never prompt" part means that (a) `-f` overrides any previously specified `-i` or `-I` option, and (b) write-protected files will be deleted without asking.]
### Example
Without `-f`, `rm` will complain about missing files:
$ rm nonesuch
rm: cannot remove ‘nonesuch’: No such file or directory
With `-f`, it will be silent:
$ rm -f nonesuch
$