diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index b09badd..ca51dc3 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -221,6 +221,7 @@ type op =
   | PrintObj of int
   | Verify of string
   | MarkAs of string
+  | RemoveMark of string
   | ExtractStructTree
   | ReplaceStructTree of string
   | SetLanguage of string
@@ -368,6 +369,7 @@ let string_of_op = function
   | PrintObj _ -> "PrintObj"
   | Verify _ -> "Verify"
   | MarkAs _ -> "MarkAs"
+  | RemoveMark _ -> "RemoveMark"
   | ExtractStructTree -> "ExtractStructTree"
   | ReplaceStructTree _ -> "ReplaceStructTree"
   | SetLanguage _ -> "SetLanguage"
@@ -891,7 +893,7 @@ let banned banlist = function
   | AddPageLabels | RemovePageLabels | OutputJSON | OCGCoalesce
   | OCGRename | OCGList | OCGOrderAll | PrintFontEncoding _ | TableOfContents | Typeset _ | Composition _
   | TextWidth _ | SetAnnotations _ | CopyAnnotations _ | ExtractStream _ | PrintObj _
-  | Verify _ | MarkAs _ | ExtractStructTree | ReplaceStructTree _ | SetLanguage _ 
+  | Verify _ | MarkAs _ | RemoveMark _ | ExtractStructTree | ReplaceStructTree _ | SetLanguage _ 
      -> false (* Always allowed *)
   (* Combine pages is not allowed because we would not know where to get the
   -recrypt from -- the first or second file? *)
@@ -2819,6 +2821,7 @@ and specs =
    ("-json", Arg.Unit (fun () -> args.format_json <- true), "Format output as JSON");
    ("-verify", Arg.String (fun s -> setop (Verify s) ()), "Verify conformance to a standard");
    ("-mark-as", Arg.String (fun s -> setop (MarkAs s) ()), "Mark as conforming to a standard");
+   ("-remove-mark", Arg.String (fun s -> setop (RemoveMark s) ()), "Remove conformance mark");
    ("-extract-struct-tree", Arg.Unit (fun () -> setop ExtractStructTree ()), "Extract structure tree in JSON format");
    ("-replace-struct-tree", Arg.String (fun s -> setop (ReplaceStructTree s) ()), "Replace structure tree from JSON");
    (* These items are undocumented *)
@@ -4474,6 +4477,14 @@ let go () =
             write_pdf false pdf
       | _ -> error "Unknown standard"
       end
+  | Some (RemoveMark standard) ->
+      begin match standard with
+      | "PDF/UA-1" ->
+          let pdf = get_single_pdf args.op false in
+            Cpdfua.remove_mark pdf;
+            write_pdf false pdf
+      | _ -> error "Unknown standard"
+      end
   | Some ExtractStructTree ->
       let pdf = get_single_pdf args.op true in
       let json = Cpdfua.extract_struct_tree pdf in
diff --git a/cpdfua.ml b/cpdfua.ml
index bc3f4e1..360f19c 100644
--- a/cpdfua.ml
+++ b/cpdfua.ml
@@ -1135,32 +1135,47 @@ let rec delete_pdfua_marker tree =
   | _ -> false
   in
     match tree with
-    | Cpdfmetadata.E (((rdf, "Description"), _), c) when rdf = Cpdfmetadata.rdf && List.exists is_pdfuaid c ->
-        Cpdfmetadata.D ""
+    | Cpdfmetadata.E (((rdf, "Description"), x), c) when rdf = Cpdfmetadata.rdf && List.exists is_pdfuaid c ->
+        Cpdfmetadata.E (((rdf, "Description"), x), keep (notpred is_pdfuaid) c)
     | Cpdfmetadata.E (x, children) ->
         Cpdfmetadata.E (x, map delete_pdfua_marker children)
     | x -> x
 
 let mark pdf =
   let pdf2 = if Cpdfmetadata.get_metadata pdf = None then Cpdfmetadata.create_metadata pdf else pdf in
-   pdf.Pdf.objects <- pdf2.Pdf.objects;
-   pdf.Pdf.trailerdict <- pdf2.Pdf.trailerdict;
-   pdf.Pdf.root <- pdf2.Pdf.root;
-   match Cpdfmetadata.get_metadata pdf with
-   | Some metadata ->
-       let dtd, tree = Cpdfmetadata.xmltree_of_bytes metadata in
-       let newtree =
-         begin match Cpdfmetadata.get_data_for Cpdfmetadata.pdfuaid "part" tree with
-         | Some _ -> insert_as_rdf_description pdfua_marker (delete_pdfua_marker tree)
-         | None -> insert_as_rdf_description pdfua_marker tree
-         end
-       in
-         let newbytes = Cpdfmetadata.bytes_of_xmltree (dtd, newtree) in
-         let pdf3 = Cpdfmetadata.set_metadata_from_bytes true newbytes pdf in
-           pdf.Pdf.objects <- pdf3.Pdf.objects;
-           pdf.Pdf.trailerdict <- pdf3.Pdf.trailerdict;
-           pdf.Pdf.root <- pdf3.Pdf.root
-   | None -> assert false
+    pdf.Pdf.objects <- pdf2.Pdf.objects;
+    pdf.Pdf.trailerdict <- pdf2.Pdf.trailerdict;
+    pdf.Pdf.root <- pdf2.Pdf.root;
+    match Cpdfmetadata.get_metadata pdf with
+    | Some metadata ->
+        let dtd, tree = Cpdfmetadata.xmltree_of_bytes metadata in
+        let newtree =
+          match Cpdfmetadata.get_data_for Cpdfmetadata.pdfuaid "part" tree with
+          | Some _ -> insert_as_rdf_description pdfua_marker (delete_pdfua_marker tree)
+          | None -> insert_as_rdf_description pdfua_marker tree
+        in
+          let newbytes = Cpdfmetadata.bytes_of_xmltree (dtd, newtree) in
+          let pdf3 = Cpdfmetadata.set_metadata_from_bytes true newbytes pdf in
+            pdf.Pdf.objects <- pdf3.Pdf.objects;
+            pdf.Pdf.trailerdict <- pdf3.Pdf.trailerdict;
+            pdf.Pdf.root <- pdf3.Pdf.root
+    | None -> assert false
+
+let remove_mark pdf =
+  match Cpdfmetadata.get_metadata pdf with
+  | Some metadata ->
+      let dtd, tree = Cpdfmetadata.xmltree_of_bytes metadata in
+      let newtree =
+        match Cpdfmetadata.get_data_for Cpdfmetadata.pdfuaid "part" tree with
+        | Some _ -> delete_pdfua_marker tree
+        | None -> tree
+      in
+        let newbytes = Cpdfmetadata.bytes_of_xmltree (dtd, newtree) in
+        let pdf3 = Cpdfmetadata.set_metadata_from_bytes true newbytes pdf in
+          pdf.Pdf.objects <- pdf3.Pdf.objects;
+          pdf.Pdf.trailerdict <- pdf3.Pdf.trailerdict;
+          pdf.Pdf.root <- pdf3.Pdf.root
+  | None -> ()
 
 let extract_struct_tree pdf =
   match Pdf.lookup_obj pdf pdf.Pdf.root with
diff --git a/cpdfua.mli b/cpdfua.mli
index a5c433c..a9dd682 100644
--- a/cpdfua.mli
+++ b/cpdfua.mli
@@ -5,6 +5,8 @@ val test_matterhorn_json : Pdf.t -> Cpdfyojson.Safe.t
 
 val mark : Pdf.t -> unit
 
+val remove_mark : Pdf.t -> unit
+
 val extract_struct_tree : Pdf.t -> Cpdfyojson.Safe.t
 
 val replace_struct_tree : Pdf.t -> Cpdfyojson.Safe.t -> unit