Index: src/OFCountedSet.m
==================================================================
--- src/OFCountedSet.m
+++ src/OFCountedSet.m
@@ -262,9 +262,24 @@
 				[self addObject: object];
 		}
 	} else
 		for (id object in set)
 			[self addObject: object];
+
+	objc_autoreleasePoolPop(pool);
+}
+
+- (void)removeAllObjects
+{
+	void *pool = objc_autoreleasePoolPush();
+	OFSet *copy = [[self copy] autorelease];
+
+	for (id object in copy) {
+		size_t count = [self countForObject: object];
+
+		for (size_t i = 0; i < count; i++)
+			[self removeObject: object];
+	}
 
 	objc_autoreleasePoolPop(pool);
 }
 @end

Index: src/OFCountedSet_hashtable.m
==================================================================
--- src/OFCountedSet_hashtable.m
+++ src/OFCountedSet_hashtable.m
@@ -208,10 +208,15 @@
 		[_mapTable setObject: (void *)(uintptr_t)count
 			      forKey: object];
 	else
 		[_mapTable removeObjectForKey: object];
 }
+
+- (void)removeAllObjects
+{
+	[_mapTable removeAllObjects];
+}
 
 - (void)makeImmutable
 {
 }
 @end

Index: src/OFMutableSet.h
==================================================================
--- src/OFMutableSet.h
+++ src/OFMutableSet.h
@@ -79,10 +79,15 @@
  *
  * @param set The set to create the union with
  */
 - (void)unionSet: (OFSet OF_GENERIC(ObjectType) *)set;
 
+/*!
+ * @brief Removes all objects from the set.
+ */
+- (void)removeAllObjects;
+
 /*!
  * @brief Converts the mutable set to an immutable set.
  */
 - (void)makeImmutable;
 #if !defined(OF_HAVE_GENERICS) && !defined(DOXYGEN)

Index: src/OFMutableSet.m
==================================================================
--- src/OFMutableSet.m
+++ src/OFMutableSet.m
@@ -191,10 +191,21 @@
 - (void)unionSet: (OFSet *)set
 {
 	for (id object in set)
 		[self addObject: object];
 }
+
+- (void)removeAllObjects
+{
+	void *pool = objc_autoreleasePoolPush();
+	OFSet *copy = [[self copy] autorelease];
+
+	for (id object in copy)
+		[self removeObject: object];
+
+	objc_autoreleasePoolPop(pool);
+}
 
 - (void)makeImmutable
 {
 }
 @end

Index: src/OFMutableSet_hashtable.m
==================================================================
--- src/OFMutableSet_hashtable.m
+++ src/OFMutableSet_hashtable.m
@@ -35,11 +35,16 @@
 
 - (void)removeObject: (id)object
 {
 	[_mapTable removeObjectForKey: object];
 }
+
+- (void)removeAllObjects
+{
+	[_mapTable removeAllObjects];
+}
 
 - (void)makeImmutable
 {
 	object_setClass(self, [OFSet_hashtable class]);
 }
 @end

Index: tests/OFSetTests.m
==================================================================
--- tests/OFSetTests.m
+++ tests/OFSetTests.m
@@ -88,10 +88,14 @@
 	TEST(@"-[unionSet:]",
 	    R([mutableSet unionSet: [OFSet setWithObjects: @"x", @"bar",
 	    nil]]) && [mutableSet isEqual: [OFSet setWithObjects: @"baz",
 	    @"bar", @"x", nil]])
 
+	TEST(@"-[removeAllObjects]",
+	    R([mutableSet removeAllObjects]) &&
+	    [mutableSet isEqual: [OFSet set]])
+
 	ok = true;
 	i = 0;
 
 	for (OFString *s in set1) {
 		switch (i) {
@@ -120,10 +124,12 @@
 		ok = false;
 
 	TEST(@"Fast enumeration", ok)
 
 	ok = false;
+	[mutableSet addObject: @"foo"];
+	[mutableSet addObject: @"bar"];
 	@try {
 		for (OFString *s in mutableSet)
 			[mutableSet removeObject: s];
 	} @catch (OFEnumerationMutationException *e) {
 		ok = true;