True i thought about tr/// too... but "a range of chars except one", could also be read "a range of chars PLUS one" (i like to reverse things up). tr/// also offer a complement modifier to it.
So when i need to delete chars, it seems more simple to write the one i actually want to keep, preventing me to forget some:

$_ = "123,Let's keep letters!\nAnd new lines..."
tr/A-Za-z \n//cd;
print;

will print:

Lets keep letters
And new lines

Creating that range could be easier...

It's just my two cents.
Freddo