diff --git a/components/compat/compatcomponent.cpp b/components/compat/compatcomponent.cpp
index 4af6b84cc..0e82e13ef 100644
--- a/components/compat/compatcomponent.cpp
+++ b/components/compat/compatcomponent.cpp
@@ -181,6 +181,9 @@ void CompatComponent::DumpComments(ofstream& fp, const DynamicObject::Ptr& owner
 	String id;
 	Dictionary::Ptr comment;
 	BOOST_FOREACH(tie(id, comment), comments) {
+		if (CommentProcessor::IsCommentExpired(comment))
+			continue;
+
 		/* There's no way for us to dump comments that haven't been
 		 * assigned a legacy ID yet. */
 		if (!comment->Contains("legacy_id"))
@@ -228,6 +231,9 @@ void CompatComponent::DumpDowntimes(ofstream& fp, const DynamicObject::Ptr& owne
 	String id;
 	Dictionary::Ptr downtime;
 	BOOST_FOREACH(tie(id, downtime), downtimes) {
+		if (DowntimeProcessor::IsDowntimeExpired(downtime))
+			continue;
+
 		/* There's no way for us to dump downtimes that haven't been
 		 * assigned a legacy ID yet. */
 		if (!downtime->Contains("legacy_id"))
diff --git a/lib/icinga/commentprocessor.cpp b/lib/icinga/commentprocessor.cpp
index d0485f0a1..5703c2c9a 100644
--- a/lib/icinga/commentprocessor.cpp
+++ b/lib/icinga/commentprocessor.cpp
@@ -25,6 +25,7 @@ int CommentProcessor::m_NextCommentID = 1;
 map<int, String> CommentProcessor::m_LegacyCommentCache;
 map<String, DynamicObject::WeakPtr> CommentProcessor::m_CommentCache;
 bool CommentProcessor::m_CommentCacheValid;
+Timer::Ptr CommentProcessor::m_CommentExpireTimer;
 
 int CommentProcessor::GetNextCommentID(void)
 {
@@ -108,6 +109,13 @@ Dictionary::Ptr CommentProcessor::GetCommentByID(const String& id)
 	return Dictionary::Ptr();
 }
 
+bool CommentProcessor::IsCommentExpired(const Dictionary::Ptr& comment)
+{
+	double expire_time = comment->Get("expire_time");
+
+	return (expire_time != 0 && expire_time < Utility::GetTime());
+}
+
 void CommentProcessor::InvalidateCommentCache(void)
 {
 	m_CommentCacheValid = false;
@@ -170,5 +178,49 @@ void CommentProcessor::ValidateCommentCache(void)
 	}
 
 	m_CommentCacheValid = true;
+
+	if (!m_CommentExpireTimer) {
+		m_CommentExpireTimer = boost::make_shared<Timer>();
+		m_CommentExpireTimer->SetInterval(300);
+		m_CommentExpireTimer->OnTimerExpired.connect(boost::bind(&CommentProcessor::CommentExpireTimerHandler));
+		m_CommentExpireTimer->Start();
+	}
+}
+
+void CommentProcessor::RemoveExpiredComments(const DynamicObject::Ptr& owner)
+{
+	Dictionary::Ptr comments = owner->Get("comments");
+
+	if (!comments)
+		return;
+
+	vector<String> expiredComments;
+
+	String id;
+	Dictionary::Ptr comment;
+	BOOST_FOREACH(tie(id, comment), comments) {
+		if (IsCommentExpired(comment))
+			expiredComments.push_back(id);
+	}
+
+	if (expiredComments.size() > 0) {
+		BOOST_FOREACH(id, expiredComments) {
+			comments->Remove(id);
+		}
+
+		owner->Touch("comments");
+	}
+}
+
+void CommentProcessor::CommentExpireTimerHandler(void)
+{
+	DynamicObject::Ptr object;
+	BOOST_FOREACH(tie(tuples::ignore, object), DynamicType::GetByName("Host")->GetObjects()) {
+		RemoveExpiredComments(object);
+	}
+
+	BOOST_FOREACH(tie(tuples::ignore, object), DynamicType::GetByName("Service")->GetObjects()) {
+		RemoveExpiredComments(object);
+	}
 }
 
diff --git a/lib/icinga/commentprocessor.h b/lib/icinga/commentprocessor.h
index 32ad57363..fb39ccdb5 100644
--- a/lib/icinga/commentprocessor.h
+++ b/lib/icinga/commentprocessor.h
@@ -52,6 +52,8 @@ public:
 	static DynamicObject::Ptr GetOwnerByCommentID(const String& id);
 	static Dictionary::Ptr GetCommentByID(const String& id);
 
+	static bool IsCommentExpired(const Dictionary::Ptr& comment);
+
 	static void InvalidateCommentCache(void);
 	static void ValidateCommentCache(void);
 
@@ -61,10 +63,14 @@ private:
 	static map<int, String> m_LegacyCommentCache;
 	static map<String, DynamicObject::WeakPtr> m_CommentCache;
 	static bool m_CommentCacheValid;
+	static Timer::Ptr m_CommentExpireTimer;
 
 	CommentProcessor(void);
 
+	static void CommentExpireTimerHandler(void);
+
 	static void AddCommentsToCache(const DynamicObject::Ptr& owner);
+	static void RemoveExpiredComments(const DynamicObject::Ptr& owner);
 };
 
 }
diff --git a/lib/icinga/downtimeprocessor.cpp b/lib/icinga/downtimeprocessor.cpp
index a62931f01..979995722 100644
--- a/lib/icinga/downtimeprocessor.cpp
+++ b/lib/icinga/downtimeprocessor.cpp
@@ -25,6 +25,7 @@ int DowntimeProcessor::m_NextDowntimeID = 1;
 map<int, String> DowntimeProcessor::m_LegacyDowntimeCache;
 map<String, DynamicObject::WeakPtr> DowntimeProcessor::m_DowntimeCache;
 bool DowntimeProcessor::m_DowntimeCacheValid;
+Timer::Ptr DowntimeProcessor::m_DowntimeExpireTimer;
 
 int DowntimeProcessor::GetNextDowntimeID(void)
 {
@@ -109,19 +110,24 @@ bool DowntimeProcessor::IsDowntimeActive(const Dictionary::Ptr& downtime)
 {
 	double now = Utility::GetTime();
 
-	if (now < static_cast<double>(downtime->Get("start_time")) ||
-	    now > static_cast<double>(downtime->Get("end_time")))
+	if (now < downtime->Get("start_time") ||
+	    now > downtime->Get("end_time"))
 		return false;
 
 	if (static_cast<bool>(downtime->Get("fixed")))
 		return true;
 
-	double triggerTime = static_cast<double>(downtime->Get("trigger_time"));
+	double triggerTime = downtime->Get("trigger_time");
 
 	if (triggerTime == 0)
 		return false;
 
-	return (triggerTime + static_cast<double>(downtime->Get("duration")) < now);
+	return (triggerTime + downtime->Get("duration") < now);
+}
+
+bool DowntimeProcessor::IsDowntimeExpired(const Dictionary::Ptr& downtime)
+{
+	return (downtime->Get("end_time") < Utility::GetTime());
 }
 
 void DowntimeProcessor::InvalidateDowntimeCache(void)
@@ -141,6 +147,8 @@ void DowntimeProcessor::AddDowntimesToCache(const DynamicObject::Ptr& owner)
 	String id;
 	Dictionary::Ptr downtime;
 	BOOST_FOREACH(tie(id, downtime), downtimes) {
+		double end_time = downtime->Get("end_time");
+
 		int legacy_id;
 
 		if (!downtime->Contains("legacy_id")) {
@@ -185,5 +193,49 @@ void DowntimeProcessor::ValidateDowntimeCache(void)
 	}
 
 	m_DowntimeCacheValid = true;
+
+	if (!m_DowntimeExpireTimer) {
+		m_DowntimeExpireTimer = boost::make_shared<Timer>();
+		m_DowntimeExpireTimer->SetInterval(300);
+		m_DowntimeExpireTimer->OnTimerExpired.connect(boost::bind(&DowntimeProcessor::DowntimeExpireTimerHandler));
+		m_DowntimeExpireTimer->Start();
+	}
+}
+
+void DowntimeProcessor::RemoveExpiredDowntimes(const DynamicObject::Ptr& owner)
+{
+	Dictionary::Ptr downtimes = owner->Get("downtimes");
+
+	if (!downtimes)
+		return;
+
+	vector<String> expiredDowntimes;
+
+	String id;
+	Dictionary::Ptr downtime;
+	BOOST_FOREACH(tie(id, downtime), downtimes) {
+		if (IsDowntimeExpired(downtime))
+			expiredDowntimes.push_back(id);
+	}
+
+	if (expiredDowntimes.size() > 0) {
+		BOOST_FOREACH(id, expiredDowntimes) {
+			downtimes->Remove(id);
+		}
+
+		owner->Touch("downtimes");
+	}
+}
+
+void DowntimeProcessor::DowntimeExpireTimerHandler(void)
+{
+	DynamicObject::Ptr object;
+	BOOST_FOREACH(tie(tuples::ignore, object), DynamicType::GetByName("Host")->GetObjects()) {
+		RemoveExpiredDowntimes(object);
+	}
+
+	BOOST_FOREACH(tie(tuples::ignore, object), DynamicType::GetByName("Service")->GetObjects()) {
+		RemoveExpiredDowntimes(object);
+	}
 }
 
diff --git a/lib/icinga/downtimeprocessor.h b/lib/icinga/downtimeprocessor.h
index 6612a63ba..db8913d1b 100644
--- a/lib/icinga/downtimeprocessor.h
+++ b/lib/icinga/downtimeprocessor.h
@@ -45,6 +45,7 @@ public:
 	static Dictionary::Ptr GetDowntimeByID(const String& id);
 
 	static bool IsDowntimeActive(const Dictionary::Ptr& downtime);
+	static bool IsDowntimeExpired(const Dictionary::Ptr& downtime);
 
 	static void InvalidateDowntimeCache(void);
 	static void ValidateDowntimeCache(void);
@@ -55,10 +56,14 @@ private:
 	static map<int, String> m_LegacyDowntimeCache;
 	static map<String, DynamicObject::WeakPtr> m_DowntimeCache;
 	static bool m_DowntimeCacheValid;
+	static Timer::Ptr m_DowntimeExpireTimer;
 
 	DowntimeProcessor(void);
 
+	static void DowntimeExpireTimerHandler(void);
+
 	static void AddDowntimesToCache(const DynamicObject::Ptr& owner);
+	static void RemoveExpiredDowntimes(const DynamicObject::Ptr& owner);
 };
 
 }