Remove all annotations from a PDF document

remove-annotations.sh

pdftk original.pdf output uncompressed.pdf uncompress
LANG=C sed -n '/^\/Annots/!p' uncompressed.pdf > stripped.pdf
pdftk stripped.pdf output final.pdf compress

Be aware that pdftk requires gcj, which was deprecated in 2017. This is old software that needs to be updated.

Just for convenience for anyone finding this via google like me: This is the code to remove all annotations from all pdfs in a directory.

# these are needed on Mac
export LC_CTYPE=C
export LANG=C

# cd /directory/with/pdfs/

for file in *.pdf
do
    outname=`sed -e "s/\.pdf$/_.pdf/"<<<"$file"`
    pdftk $file output - uncompress | sed '/^\/Annots/d' | pdftk - output $outname compress
    echo "$file: done"
done

Is it possible to reduce the opacity?

this leave me with a PDF with a broken xref table :(

pdfcpu annotations remove my.pdf

works reasonably well :)
https://pdfcpu.io/annot/annot

Still works!