diff --git a/ngcp/dp.lua b/ngcp/dp.lua
index c6dc422..75e5fbb 100644
--- a/ngcp/dp.lua
+++ b/ngcp/dp.lua
@@ -48,8 +48,17 @@ NGCPDomainPrefs_MT = { __index = NGCPDomainPrefs }
         return keys
     end
 
-    function NGCPDomainPrefs:clean()
-        sr.pv.unset("$xavp(domain)")
+    function NGCPDomainPrefs:clean(vtype)
+        local xavp
+        if not vtype then
+            sr.pv.unset("$xavp(domain)")
+        elseif vtype == 'callee' then
+            xavp = NGCPXAvp:new('callee','domain',{})
+            xavp:clean()
+        elseif vtype == 'caller' then
+            xavp = NGCPXAvp:new('caller','domain',{})
+            xavp:clean()
+        end
     end
 -- class
 --EOF
\ No newline at end of file
diff --git a/tests/ngcp_dp.lua b/tests/ngcp_dp.lua
index 980a7f4..c59e782 100644
--- a/tests/ngcp_dp.lua
+++ b/tests/ngcp_dp.lua
@@ -94,6 +94,63 @@ TestNGCPDomainPrefs = {} --class
         assertEquals(sr.pv.get("$xavp(domain[1]=>sst_refresh_method)"), "UPDATE_FALLBACK_INVITE")
         assertItemsEquals(keys, {"sst_enable", "sst_refresh_method"})
     end
+
+    function TestNGCPDomainPrefs:test_clean()
+        local xavp = NGCPXAvp:new('callee','domain',{})
+        xavp("testid",1)
+        xavp("foo","foo")
+        assertEquals(sr.pv.get("$xavp(domain[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(domain[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(domain[0]=>dummy)"),"caller")
+        self.d:clean()
+        assertFalse(sr.pv.get("$xavp(domain[0]=>dummy)"))
+        assertFalse(sr.pv.get("$xavp(domain[1]=>dummy)"))
+        assertFalse(sr.pv.get("$xavp(domain)"))
+    end
+
+    function TestNGCPDomainPrefs:test_callee_clean()
+        local callee_xavp = NGCPXAvp:new('callee','domain',{})
+        callee_xavp("testid",1)
+        callee_xavp("foo","foo")
+        local caller_xavp = NGCPXAvp:new('caller','domain',{})
+        caller_xavp("other",1)
+        caller_xavp("otherfoo","foo")
+        assertEquals(sr.pv.get("$xavp(domain[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(domain[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(domain[0]=>dummy)"),"caller")
+        assertEquals(sr.pv.get("$xavp(domain[0]=>other)"),1)
+        assertEquals(sr.pv.get("$xavp(domain[0]=>otherfoo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(domain[1]=>dummy)"),"callee")
+        self.d:clean('callee')
+        assertEquals(sr.pv.get("$xavp(domain[0]=>dummy)"),'caller')
+        assertFalse(sr.pv.get("$xavp(domain[1]=>testid)"))
+        assertFalse(sr.pv.get("$xavp(domain[1]=>foo)"))
+        assertEquals(sr.pv.get("$xavp(domain[0]=>other)"),1)
+        assertEquals(sr.pv.get("$xavp(domain[0]=>otherfoo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(domain[1]=>dummy)"),"callee")
+    end
+
+    function TestNGCPDomainPrefs:test_caller_clean()
+        local callee_xavp = NGCPXAvp:new('callee','domain',{})
+        callee_xavp("testid",1)
+        callee_xavp("foo","foo")
+        local caller_xavp = NGCPXAvp:new('caller','domain',{})
+        caller_xavp("other",1)
+        caller_xavp("otherfoo","foo")
+        assertEquals(sr.pv.get("$xavp(domain[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(domain[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(domain[0]=>dummy)"),"caller")
+        assertEquals(sr.pv.get("$xavp(domain[0]=>other)"),1)
+        assertEquals(sr.pv.get("$xavp(domain[0]=>otherfoo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(domain[1]=>dummy)"),"callee")
+        self.d:clean('caller')
+        assertEquals(sr.pv.get("$xavp(domain[0]=>dummy)"),'caller')
+        assertFalse(sr.pv.get("$xavp(domain[0]=>other)"))
+        assertFalse(sr.pv.get("$xavp(domain[0]=>otherfoo)"))
+        assertEquals(sr.pv.get("$xavp(domain[1]=>testid)"),1)
+        assertEquals(sr.pv.get("$xavp(domain[1]=>foo)"),"foo")
+        assertEquals(sr.pv.get("$xavp(domain[1]=>dummy)"),"callee")
+    end
 -- class TestNGCPDomainPrefs
 
 ---- Control test output: