diff --git a/app/src/androidTest/java/de/westnordost/streetcomplete/data/osm/persist/OsmQuestDaoTest.java b/app/src/androidTest/java/de/westnordost/streetcomplete/data/osm/persist/OsmQuestDaoTest.java
index dde1444b72..3d03947ca4 100644
--- a/app/src/androidTest/java/de/westnordost/streetcomplete/data/osm/persist/OsmQuestDaoTest.java
+++ b/app/src/androidTest/java/de/westnordost/streetcomplete/data/osm/persist/OsmQuestDaoTest.java
@@ -157,6 +157,20 @@ public void testDeleteAllClosed()
 		assertEquals(2,dao.deleteAllClosed(System.currentTimeMillis() + 10000L));
 	}
 
+	public void testDeleteAllUnsolved()
+	{
+		OsmQuest quest1 = createNewQuest(1, Element.Type.NODE);
+		quest1.setStatus(QuestStatus.NEW);
+		OsmQuest quest2 = createNewQuest(2, Element.Type.NODE);
+		quest2.setStatus(QuestStatus.HIDDEN);
+		OsmQuest quest3 = createNewQuest(3, Element.Type.NODE);
+		quest3.setStatus(QuestStatus.ANSWERED);
+
+		addToDaos(quest1, quest2, quest3);
+
+		assertEquals(2,dao.deleteAllUnsolved(System.currentTimeMillis() + 10000L));
+	}
+
 	public void testDeleteReverted()
 	{
 		ElementGeometry geom = new ElementGeometry(new OsmLatLon(5,5));
diff --git a/app/src/main/java/de/westnordost/streetcomplete/ApplicationConstants.java b/app/src/main/java/de/westnordost/streetcomplete/ApplicationConstants.java
index 63b9304958..3a2dfe2258 100644
--- a/app/src/main/java/de/westnordost/streetcomplete/ApplicationConstants.java
+++ b/app/src/main/java/de/westnordost/streetcomplete/ApplicationConstants.java
@@ -29,7 +29,12 @@ public class ApplicationConstants
 
 	/** a "best before" duration for quests. Quests will not be downloaded again for any tile
 	 *  before the time expired */
-	public static final int REFRESH_QUESTS_AFTER = 7*24*60*60*1000; // one week in ms
+	public static final long REFRESH_QUESTS_AFTER = 7L*24*60*60*1000; // 1 week in ms
+	/** the duration after which quests will be deleted from the database if unsolved */
+	public static final long DELETE_UNSOLVED_QUESTS_AFTER = 1L*30*24*60*60*1000; // 1 months in ms
+
+	/** the max age of the undo history - one cannot undo changes older than X */
+	public static final long MAX_QUEST_UNDO_HISTORY_AGE = 24*60*60*1000; // 1 day in ms
 
 	public static final String AVATARS_CACHE_DIRECTORY = "osm_user_avatars";
 
diff --git a/app/src/main/java/de/westnordost/streetcomplete/MainActivity.java b/app/src/main/java/de/westnordost/streetcomplete/MainActivity.java
index ca09e326fd..04a934e0d8 100644
--- a/app/src/main/java/de/westnordost/streetcomplete/MainActivity.java
+++ b/app/src/main/java/de/westnordost/streetcomplete/MainActivity.java
@@ -239,6 +239,11 @@ public void onServiceDisconnected(ComponentName className)
 		mapFragment = (QuestsMapFragment) getSupportFragmentManager().findFragmentById(R.id.map_fragment);
 		mapFragment.getMapAsync(BuildConfig.MAPZEN_API_KEY);
 		updateMapQuestOffsets();
+
+		if(savedInstanceState == null)
+		{
+			questController.deleteOld();
+		}
 	}
 
 	@Override public void onStart()
diff --git a/app/src/main/java/de/westnordost/streetcomplete/data/AQuestDao.java b/app/src/main/java/de/westnordost/streetcomplete/data/AQuestDao.java
index 6b452e2a64..9ce84a9e91 100644
--- a/app/src/main/java/de/westnordost/streetcomplete/data/AQuestDao.java
+++ b/app/src/main/java/de/westnordost/streetcomplete/data/AQuestDao.java
@@ -177,6 +177,17 @@ public int deleteAllClosed(long olderThan)
 				QuestStatus.CLOSED.name(), QuestStatus.REVERT.name(), String.valueOf(olderThan)});
 	}
 
+	public int deleteAllUnsolved(long olderThan)
+	{
+		String statusCol = getQuestStatusColumnName();
+		String query = "(" + statusCol + " = ? OR " + statusCol + " = ?) AND " +
+			getLastChangedColumnName() + " < ?";
+
+		SQLiteDatabase db = dbHelper.getWritableDatabase();
+		return db.delete(getTableName(), query, new String[]{
+			QuestStatus.NEW.name(), QuestStatus.HIDDEN.name(), String.valueOf(olderThan)});
+	}
+
 	public int addAll(Collection<T> quests)
 	{
 		return insertAll(quests, false);
diff --git a/app/src/main/java/de/westnordost/streetcomplete/data/QuestController.java b/app/src/main/java/de/westnordost/streetcomplete/data/QuestController.java
index 360b9c7b01..0cd1cea20a 100644
--- a/app/src/main/java/de/westnordost/streetcomplete/data/QuestController.java
+++ b/app/src/main/java/de/westnordost/streetcomplete/data/QuestController.java
@@ -421,4 +421,22 @@ public void upload()
 	{
 		context.startService(new Intent(context, QuestChangesUploadService.class));
 	}
+
+	public void deleteOld()
+	{
+		workerHandler.post(() ->
+		{
+			long timestamp = System.currentTimeMillis() - ApplicationConstants.DELETE_UNSOLVED_QUESTS_AFTER;
+			int deleted = osmQuestDB.deleteAllUnsolved(timestamp);
+			deleted += osmNoteQuestDB.deleteAllUnsolved(timestamp);
+
+			if(deleted > 0)
+			{
+				Log.d(TAG, "Deleted "+ deleted + " old unsolved quests");
+
+				osmElementDB.deleteUnreferenced();
+				geometryDB.deleteUnreferenced();
+			}
+		});
+	}
 }
diff --git a/app/src/main/java/de/westnordost/streetcomplete/data/osm/download/OsmQuestDownload.java b/app/src/main/java/de/westnordost/streetcomplete/data/osm/download/OsmQuestDownload.java
index 47ff442652..1211b57c84 100644
--- a/app/src/main/java/de/westnordost/streetcomplete/data/osm/download/OsmQuestDownload.java
+++ b/app/src/main/java/de/westnordost/streetcomplete/data/osm/download/OsmQuestDownload.java
@@ -128,6 +128,7 @@ public boolean download(final OsmElementQuestType questType, BoundingBox bbox,
 		// turns out to be slow if done for every quest type
 		geometryDB.deleteUnreferenced();
 		elementDB.deleteUnreferenced();
+		questType.cleanMetadata();
 
 		int obsoleteAmount = previousQuests.size();
 		Log.i(TAG, getQuestTypeName(questType) + ": " +
diff --git a/app/src/main/java/de/westnordost/streetcomplete/data/osm/upload/AOsmQuestChangesUpload.java b/app/src/main/java/de/westnordost/streetcomplete/data/osm/upload/AOsmQuestChangesUpload.java
index 8433d8e32a..caed311d8a 100644
--- a/app/src/main/java/de/westnordost/streetcomplete/data/osm/upload/AOsmQuestChangesUpload.java
+++ b/app/src/main/java/de/westnordost/streetcomplete/data/osm/upload/AOsmQuestChangesUpload.java
@@ -173,8 +173,8 @@ public synchronized void upload(AtomicBoolean cancelState)
 
 	private void cleanUp(Set<OsmElementQuestType> questTypes)
 	{
-		long yesterday = System.currentTimeMillis() - 24 * 60 * 60 * 1000;
-		int deletedQuests = questDB.deleteAllClosed(yesterday);
+		long timestamp = System.currentTimeMillis() - ApplicationConstants.MAX_QUEST_UNDO_HISTORY_AGE;
+		int deletedQuests = questDB.deleteAllClosed(timestamp);
 		if(deletedQuests > 0)
 		{
 			elementGeometryDB.deleteUnreferenced();