diff --git a/system/exiftool b/data/exiftool.md
similarity index 83%
rename from system/exiftool
rename to data/exiftool.md
index 520b21e..86cb6bf 100644
--- a/system/exiftool
+++ b/data/exiftool.md
@@ -22,6 +22,7 @@ And overwrite all metadata:
 ```bash
 exiftool -all= -overwrite_original -ext jpg .
 ```
+(NB: This does not work on pdf data. See [here](pdf_erasure.md) for erasing all pdf data)
 
 Or just GPS data:
 
@@ -36,3 +37,4 @@ identify -verbose
 ```
 
 
+
diff --git a/data/pdf_erasure.md b/data/pdf_erasure.md
new file mode 100644
index 0000000..2f3947d
--- /dev/null
+++ b/data/pdf_erasure.md
@@ -0,0 +1,25 @@
+---
+title: "PDF Metadata Erasure"
+tags: [ "Documentation", "Metadata", "Ghost Script" ]
+---
+
+Make a text file called 'pdfmark.txt'.
+
+
+```text
+[ /Title ()
+/Author ()
+/Subject ()
+/Creator ()
+/ModDate ()
+/Producer ()
+/Keywords ()
+/CreationDate ()
+/DOCINFO pdfmark
+```
+
+Then run:
+
+```bash
+gs -o output.pdf -sDEVICE=pdfwrite "$FILE".pdf pdfmark.txt
+```