but they simply don't show up in my output rtf file.

Great start, but your code doesn't demonstrate that -- it doesn't generate a rtf file which doesn't show {}

All your examples s/\{/{/g; will replace braces all day and all night :) but they won't necessarily make them appear visible in a rtf document :)

It is basic escaping problem -- { and } are special in RTF, so use one of RTF::Parser / RTF::Lexer / RTF::Writer