diff --git a/ngcp/pp.lua b/ngcp/pp.lua
index a655cab..fd4663b 100644
--- a/ngcp/pp.lua
+++ b/ngcp/pp.lua
@@ -43,8 +43,17 @@ NGCPPeerPrefs_MT = { __index = NGCPPeerPrefs }
         con:close()
     end
 
-    function NGCPPeerPrefs:clean()
-        sr.pv.unset("$xavp(peer)")
+    function NGCPPeerPrefs:clean(vtype)
+        local xavp
+        if not vtype then
+            sr.pv.unset("$xavp(peer)")
+        elseif vtype == 'callee' then
+            xavp = NGCPXAvp:new('callee','peer',{})
+            xavp:clean()
+        elseif vtype == 'caller' then
+            xavp = NGCPXAvp:new('caller','peer',{})
+            xavp:clean()
+        end
     end
 -- class
 --EOF
\ No newline at end of file
diff --git a/ngcp/up.lua b/ngcp/up.lua
index 15088c1..32e2faf 100644
--- a/ngcp/up.lua
+++ b/ngcp/up.lua
@@ -48,8 +48,17 @@ NGCPUserPrefs_MT = { __index = NGCPUserPrefs }
         return keys
     end
 
-    function NGCPUserPrefs:clean(...)
-        sr.pv.unset("$xavp(user)")
+    function NGCPUserPrefs:clean(vtype)
+        local xavp
+        if not vtype then
+            sr.pv.unset("$xavp(user)")
+        elseif vtype == 'callee' then
+            xavp = NGCPXAvp:new('callee','user',{})
+            xavp:clean()
+        elseif vtype == 'caller' then
+            xavp = NGCPXAvp:new('caller','user',{})
+            xavp:clean()
+        end
     end
 -- class
 --EOF
\ No newline at end of file
diff --git a/tests/ngcp_pp.lua b/tests/ngcp_pp.lua
index 22aa3ff..869184d 100644
--- a/tests/ngcp_pp.lua
+++ b/tests/ngcp_pp.lua
@@ -102,6 +102,63 @@ TestNGCPPeerPrefs = {} --class
         assertEquals(sr.pv.get("$xavp(domain[1]=>sst_refresh_method)"), "UPDATE_FALLBACK_INVITE")
         assertIsNil(self.d.xavp("error_key"))
     end
+
+    function TestNGCPPeerPrefs:test_clean()
+        local xavp = NGCPXAvp:new('callee','peer',{})
+        xavp("testid",1)
+        xavp("foo","foo")
+        assertEquals(sr.pv.get("$xavp(peer[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(peer[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(peer[0]=>dummy)"),"caller")
+        self.d:clean()
+        assertFalse(sr.pv.get("$xavp(peer[0]=>dummy)"))
+        assertFalse(sr.pv.get("$xavp(peer[1]=>dummy)"))
+        assertFalse(sr.pv.get("$xavp(peer)"))
+    end
+
+    function TestNGCPPeerPrefs:test_callee_clean()
+        local callee_xavp = NGCPXAvp:new('callee','peer',{})
+        callee_xavp("testid",1)
+        callee_xavp("foo","foo")
+        local caller_xavp = NGCPXAvp:new('caller','peer',{})
+        caller_xavp("other",1)
+        caller_xavp("otherfoo","foo")
+        assertEquals(sr.pv.get("$xavp(peer[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(peer[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(peer[0]=>dummy)"),"caller")
+        assertEquals(sr.pv.get("$xavp(peer[0]=>other)"),1)
+        assertEquals(sr.pv.get("$xavp(peer[0]=>otherfoo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(peer[1]=>dummy)"),"callee")
+        self.d:clean('callee')
+        assertEquals(sr.pv.get("$xavp(peer[0]=>dummy)"),'caller')
+        assertFalse(sr.pv.get("$xavp(peer[1]=>testid)"))
+        assertFalse(sr.pv.get("$xavp(peer[1]=>foo)"))
+        assertEquals(sr.pv.get("$xavp(peer[0]=>other)"),1)
+        assertEquals(sr.pv.get("$xavp(peer[0]=>otherfoo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(peer[1]=>dummy)"),"callee")
+    end
+
+    function TestNGCPPeerPrefs:test_caller_clean()
+        local callee_xavp = NGCPXAvp:new('callee','peer',{})
+        callee_xavp("testid",1)
+        callee_xavp("foo","foo")
+        local caller_xavp = NGCPXAvp:new('caller','peer',{})
+        caller_xavp("other",1)
+        caller_xavp("otherfoo","foo")
+        assertEquals(sr.pv.get("$xavp(peer[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(peer[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(peer[0]=>dummy)"),"caller")
+        assertEquals(sr.pv.get("$xavp(peer[0]=>other)"),1)
+        assertEquals(sr.pv.get("$xavp(peer[0]=>otherfoo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(peer[1]=>dummy)"),"callee")
+        self.d:clean('caller')
+        assertEquals(sr.pv.get("$xavp(peer[0]=>dummy)"),'caller')
+        assertFalse(sr.pv.get("$xavp(peer[0]=>other)"))
+        assertFalse(sr.pv.get("$xavp(peer[0]=>otherfoo)"))
+        assertEquals(sr.pv.get("$xavp(peer[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(peer[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(peer[1]=>dummy)"),"callee")
+    end
 -- class TestNGCPPeerPrefs
 
 ---- Control test output:
diff --git a/tests/ngcp_up.lua b/tests/ngcp_up.lua
index 2697165..9ac8bf9 100644
--- a/tests/ngcp_up.lua
+++ b/tests/ngcp_up.lua
@@ -102,6 +102,63 @@ TestNGCPUserPrefs = {} --class
         assertEquals(sr.pv.get("$xavp(user[1]=>ac)"),"1")
         assertItemsEquals(keys, {"account_id", "cli", "cc", "ac"})
     end
+    
+    function TestNGCPUserPrefs:test_clean()
+        local xavp = NGCPXAvp:new('callee','user',{})
+        xavp("testid",1)
+        xavp("foo","foo")
+        assertEquals(sr.pv.get("$xavp(user[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(user[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(user[0]=>dummy)"),"caller")
+        self.d:clean()
+        assertFalse(sr.pv.get("$xavp(user[0]=>dummy)"))
+        assertFalse(sr.pv.get("$xavp(user[1]=>dummy)"))
+        assertFalse(sr.pv.get("$xavp(user)"))
+    end
+
+    function TestNGCPUserPrefs:test_callee_clean()
+        local callee_xavp = NGCPXAvp:new('callee','user',{})
+        callee_xavp("testid",1)
+        callee_xavp("foo","foo")
+        local caller_xavp = NGCPXAvp:new('caller','user',{})
+        caller_xavp("other",1)
+        caller_xavp("otherfoo","foo")
+        assertEquals(sr.pv.get("$xavp(user[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(user[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(user[0]=>dummy)"),"caller")
+        assertEquals(sr.pv.get("$xavp(user[0]=>other)"),1)
+        assertEquals(sr.pv.get("$xavp(user[0]=>otherfoo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(user[1]=>dummy)"),"callee")
+        self.d:clean('callee')
+        assertEquals(sr.pv.get("$xavp(user[0]=>dummy)"),'caller')
+        assertFalse(sr.pv.get("$xavp(user[1]=>testid)"))
+        assertFalse(sr.pv.get("$xavp(user[1]=>foo)"))
+        assertEquals(sr.pv.get("$xavp(user[0]=>other)"),1)
+        assertEquals(sr.pv.get("$xavp(user[0]=>otherfoo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(user[1]=>dummy)"),"callee")
+    end
+
+    function TestNGCPUserPrefs:test_caller_clean()
+        local callee_xavp = NGCPXAvp:new('callee','user',{})
+        callee_xavp("testid",1)
+        callee_xavp("foo","foo")
+        local caller_xavp = NGCPXAvp:new('caller','user',{})
+        caller_xavp("other",1)
+        caller_xavp("otherfoo","foo")
+        assertEquals(sr.pv.get("$xavp(user[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(user[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(user[0]=>dummy)"),"caller")
+        assertEquals(sr.pv.get("$xavp(user[0]=>other)"),1)
+        assertEquals(sr.pv.get("$xavp(user[0]=>otherfoo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(user[1]=>dummy)"),"callee")
+        self.d:clean('caller')
+        assertEquals(sr.pv.get("$xavp(user[0]=>dummy)"),'caller')
+        assertFalse(sr.pv.get("$xavp(user[0]=>other)"))
+        assertFalse(sr.pv.get("$xavp(user[0]=>otherfoo)"))
+        assertEquals(sr.pv.get("$xavp(user[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(user[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(user[1]=>dummy)"),"callee")
+    end
 -- class TestNGCPUserPrefs
 
 ---- Control test output: