How to turn off rendering of placeholder texts in Writer's PDF export?

My letter template has a few placeholder texts, some of which are seldom/never used.
Is there a way to have them not rendered to PDF?

They are not printed when I print the document directly and OpenOffice never rendered them to PDF either.

The placeholder text are inserted via (translated from the German UI):

Insert->Field->Other->Function tab->Type:Placeholder/Format:Text/Placeholder:my-placeholder-text

Thanks for the extra info. I misunderstood your question. I see what you mean now.

I presume your reference to “placeholder texts” implies Insert > Fields > Other… > Variables tab. Are you using an Input field or a User field? The distinction is explained in this thread.