diff --git a/doc/handbook/sequences.facts b/doc/handbook/sequences.facts
index d2af03469e..68a35edc7b 100644
--- a/doc/handbook/sequences.facts
+++ b/doc/handbook/sequences.facts
@@ -132,7 +132,6 @@ ARTICLE: "sequences-adding" "Adding and appending"
 { $subsection join }
 "Mutable sequences can have elements added in-place."
 { $subsection push }
-{ $subsection adjoin }
 { $subsection nappend }
 "Subsequences can be replaced:"
 { $subsection replace-slice }
@@ -141,7 +140,6 @@ ARTICLE: "sequences-adding" "Adding and appending"
 ARTICLE: "sequences-sets" "Order-insensitive operations"
 "New sequences can be constructed by removing elements from an existing sequence:"
 { $subsection remove }
-{ $subsection prune }
 { $subsection diff }
 "Mutable sequences can have elements removed in-place:"
 { $subsection delete }
diff --git a/library/collections/sequences-epilogue.factor b/library/collections/sequences-epilogue.factor
index 8fbf0d87fc..fc2924445b 100644
--- a/library/collections/sequences-epilogue.factor
+++ b/library/collections/sequences-epilogue.factor
@@ -78,12 +78,6 @@ M: object >list ( seq -- list ) dup length 0 rot (>list) ;
 : add ( seq elt -- seq )
     swap [ push ] immutable ; flushable
 
-: adjoin ( elt seq -- )
-    2dup member? [ 2drop ] [ push ] if ;
-
-: prune ( seq -- seq )
-    dup dup length <vector> swap [ over adjoin ] each swap like ;
-
 : diff ( seq1 seq2 -- seq2-seq1 )
     [ swap member? not ] subset-with ; flushable
 
diff --git a/library/collections/sequences-epilogue.facts b/library/collections/sequences-epilogue.facts
index a5c460d686..73bf19a9c3 100644
--- a/library/collections/sequences-epilogue.facts
+++ b/library/collections/sequences-epilogue.facts
@@ -86,10 +86,6 @@ HELP: adjoin "( elt seq -- )"
 { $side-effects "seq" }
 { $errors "Throws an error if the type of " { $snippet "elt" } " is not permitted in sequences of the same class as " { $snippet "seq1" } "." } ;
 
-HELP: prune "( seq -- newseq )"
-{ $values { "seq" "a sequence" } { "newseq" "a sequence" } }
-{ $description "Outputs a new sequence of the same class as " { $snippet "seq" } " with each element appearing only once." } ;
-
 HELP: diff "( seq1 seq2 -- newseq )"
 { $values { "seq1" "a sequence" } { "seq2" "a sequence" } { "newseq" "a sequence" } }
 { $description "Outputs a sequence consisting of elements present in " { $snippet "seq2" } " but not " { $snippet "seq1" } ", comparing elements for equality." } ;
diff --git a/library/test/collections/sequences.factor b/library/test/collections/sequences.factor
index 8def7aaf83..1a230152c8 100644
--- a/library/test/collections/sequences.factor
+++ b/library/test/collections/sequences.factor
@@ -175,8 +175,6 @@ unit-test
 
 [ -1 f ] [ -1 { 1 2 3 } [ 1 = ] find* ] unit-test
 
-[ { 1 2 3 } ] [ { 1 1 2 2 3 3 } prune ] unit-test
-
 [ 0 ] [ { "a" "b" "c" } { "A" "B" "C" } mismatch ] unit-test
 
 [ 1 ] [ { "a" "b" "c" } { "a" "B" "C" } mismatch ] unit-test