Delete character using rule "s"

[whyyfmwr]

Hello,
I have a question about rule-based attack. I know I can change all "," characters to "-" by this rule:

Code:

s,-

Code:

paper,paper -> paper-paper

Is is possible to use this rule to delete all "," characters?

Code:

paper,paper -> paperpaper

I tried to use a rule

Code:

s,

but this is probably not a valid rule.