diff --git a/cache2go/cache_test.go b/cache2go/cache_test.go
index 7b915ae5a..1bae5050b 100644
--- a/cache2go/cache_test.go
+++ b/cache2go/cache_test.go
@@ -89,7 +89,7 @@ func TestCachePush(t *testing.T) {
 	CachePush("ccc_t1", "1")
 	CachePush("ccc_t1", "2")
 	v, err := GetCached("ccc_t1")
-	if err != nil || len(v.([]interface{})) != 2 {
+	if err != nil || len(v.(map[interface{}]struct{})) != 2 {
 		t.Error("Error in cache push: ", v)
 	}
 }
diff --git a/cache2go/store.go b/cache2go/store.go
index a2148ad33..1f63f7ee4 100644
--- a/cache2go/store.go
+++ b/cache2go/store.go
@@ -37,21 +37,15 @@ func (cs cacheDoubleStore) Put(key string, value interface{}) {
 }
 
 func (cs cacheDoubleStore) Append(key string, value interface{}) {
-	var elements []interface{}
-	v, err := cs.Get(key)
-	if err == nil {
-		elements = v.([]interface{})
+	var elements map[interface{}]struct{}
+	if v, err := cs.Get(key); err == nil {
+		elements = v.(map[interface{}]struct{})
+	} else {
+		elements = make(map[interface{}]struct{})
 	}
 	// check if the val is already present
-	found := false
-	for _, v := range elements {
-		if value == v {
-			found = true
-			break
-		}
-	}
-	if !found {
-		elements = append(elements, value)
+	if _, found := elements[value]; !found {
+		elements[value] = struct{}{}
 	}
 	cache.Put(key, elements)
 }
diff --git a/engine/account.go b/engine/account.go
index a089c59ac..1f6451b5d 100644
--- a/engine/account.go
+++ b/engine/account.go
@@ -160,8 +160,8 @@ func (ub *Account) getBalancesForPrefix(prefix, category string, balances Balanc
 		if b.DestinationId != "" && b.DestinationId != utils.ANY {
 			for _, p := range utils.SplitPrefix(prefix, MIN_PREFIX_MATCH) {
 				if x, err := cache2go.GetCached(DESTINATION_PREFIX + p); err == nil {
-					destIds := x.([]interface{})
-					for _, dId := range destIds {
+					destIds := x.(map[interface{}]struct{})
+					for dId, _ := range destIds {
 						if dId == b.DestinationId {
 							b.precision = len(p)
 							usefulBalances = append(usefulBalances, b)
diff --git a/engine/destinations.go b/engine/destinations.go
index b43e0d3a1..7af1d826e 100644
--- a/engine/destinations.go
+++ b/engine/destinations.go
@@ -20,11 +20,9 @@ package engine
 
 import (
 	"encoding/json"
-	"sort"
 	"strings"
 
 	"github.com/cgrates/cgrates/cache2go"
-	"github.com/cgrates/cgrates/utils"
 
 	"github.com/cgrates/cgrates/history"
 )
@@ -76,11 +74,8 @@ func (d *Destination) GetHistoryRecord() history.Record {
 // Reverse search in cache to see if prefix belongs to destination id
 func CachedDestHasPrefix(destId, prefix string) bool {
 	if cached, err := cache2go.GetCached(DESTINATION_PREFIX + prefix); err == nil {
-		for _, cachedDstId := range cached.([]interface{}) {
-			if destId == cachedDstId {
-				return true
-			}
-		}
+		_, found := cached.(map[interface{}]struct{})[destId]
+		return found
 	}
 	return false
 }
@@ -91,17 +86,16 @@ func CleanStalePrefixes(destIds []string) {
 		return
 	}
 	for prefix, idIDs := range prefixMap {
-		dIDs := idIDs.Value().([]interface{})
+		dIDs := idIDs.Value().(map[interface{}]struct{})
 		changed := false
-		sort.Sort(utils.InterfaceStrings(dIDs))
 		for _, searchedDID := range destIds {
-			if i, found := utils.GetSliceInterfaceIndex(dIDs, searchedDID); found {
+			if _, found := dIDs[searchedDID]; found {
 				if len(dIDs) == 1 {
 					// remove de prefix from cache
 					cache2go.RemKey(DESTINATION_PREFIX + prefix)
 				} else {
 					// delete the destination from list and put the new list in chache
-					dIDs[i], dIDs = dIDs[len(dIDs)-1], dIDs[:len(dIDs)-1]
+					delete(dIDs, searchedDID)
 					changed = true
 				}
 			}
diff --git a/engine/destinations_test.go b/engine/destinations_test.go
index 9eed163b4..31b9515e3 100644
--- a/engine/destinations_test.go
+++ b/engine/destinations_test.go
@@ -126,17 +126,18 @@ func TestNonCachedDestWrongPrefix(t *testing.T) {
 }
 
 func TestCleanStalePrefixes(t *testing.T) {
-	cache2go.Cache(DESTINATION_PREFIX+"1", []interface{}{"D1", "D2"})
-	cache2go.Cache(DESTINATION_PREFIX+"2", []interface{}{"D1"})
-	cache2go.Cache(DESTINATION_PREFIX+"3", []interface{}{"D2"})
+	x := struct{}{}
+	cache2go.Cache(DESTINATION_PREFIX+"1", map[interface{}]struct{}{"D1": x, "D2": x})
+	cache2go.Cache(DESTINATION_PREFIX+"2", map[interface{}]struct{}{"D1": x})
+	cache2go.Cache(DESTINATION_PREFIX+"3", map[interface{}]struct{}{"D2": x})
 	CleanStalePrefixes([]string{"D1"})
-	if r, err := cache2go.GetCached(DESTINATION_PREFIX + "1"); err != nil || len(r.([]interface{})) != 1 {
+	if r, err := cache2go.GetCached(DESTINATION_PREFIX + "1"); err != nil || len(r.(map[interface{}]struct{})) != 1 {
 		t.Error("Error cleaning stale destination ids", r)
 	}
 	if r, err := cache2go.GetCached(DESTINATION_PREFIX + "2"); err == nil {
 		t.Error("Error removing stale prefix: ", r)
 	}
-	if r, err := cache2go.GetCached(DESTINATION_PREFIX + "3"); err != nil || len(r.([]interface{})) != 1 {
+	if r, err := cache2go.GetCached(DESTINATION_PREFIX + "3"); err != nil || len(r.(map[interface{}]struct{})) != 1 {
 		t.Error("Error performing stale cleaning: ", r)
 	}
 }
diff --git a/engine/ratingprofile.go b/engine/ratingprofile.go
index 85a877823..c667ab266 100644
--- a/engine/ratingprofile.go
+++ b/engine/ratingprofile.go
@@ -127,8 +127,8 @@ func (rp *RatingProfile) GetRatingPlansForPrefix(cd *CallDescriptor) (err error)
 		} else {
 			for _, p := range utils.SplitPrefix(cd.Destination, MIN_PREFIX_MATCH) {
 				if x, err := cache2go.GetCached(DESTINATION_PREFIX + p); err == nil {
-					destIds := x.([]interface{})
-					for _, idId := range destIds {
+					destIds := x.(map[interface{}]struct{})
+					for idId, _ := range destIds {
 						dId := idId.(string)
 						if _, ok := rpl.DestinationRates[dId]; ok {
 							rps = rpl.RateIntervalList(dId)
diff --git a/engine/units_counter.go b/engine/units_counter.go
index ab975a28f..8c192c27c 100644
--- a/engine/units_counter.go
+++ b/engine/units_counter.go
@@ -78,13 +78,11 @@ func (uc *UnitsCounter) addUnits(amount float64, prefix string) {
 			}
 			for _, p := range utils.SplitPrefix(prefix, MIN_PREFIX_MATCH) {
 				if x, err := cache2go.GetCached(DESTINATION_PREFIX + p); err == nil {
-					destIds := x.([]interface{})
-					for _, dId := range destIds {
-						if dId == mb.DestinationId {
-							mb.Value += amount
-							counted = true
-							break
-						}
+					destIds := x.(map[interface{}]struct{})
+					if _, found := destIds[mb.DestinationId]; found {
+						mb.Value += amount
+						counted = true
+						break
 					}
 				}
 				if counted {
diff --git a/utils/slice.go b/utils/slice.go
index ecd80157a..964e95d75 100644
--- a/utils/slice.go
+++ b/utils/slice.go
@@ -32,16 +32,6 @@ func IsSliceMember(ss []string, s string) bool {
 	return false
 }
 
-// Binary string search in slice
-// returns true if found and the index
-func GetSliceMemberIndex(ss []string, s string) (int, bool) {
-	sort.Strings(ss)
-	if i := sort.SearchStrings(ss, s); i < len(ss) && ss[i] == s {
-		return i, true
-	}
-	return len(ss), false
-}
-
 //Iterates over slice members and returns true if one starts with prefix
 func SliceMemberHasPrefix(ss []string, prfx string) bool {
 	for _, mbr := range ss {
@@ -51,18 +41,3 @@ func SliceMemberHasPrefix(ss []string, prfx string) bool {
 	}
 	return false
 }
-
-type InterfaceStrings []interface{}
-
-func (a InterfaceStrings) Len() int           { return len(a) }
-func (a InterfaceStrings) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
-func (a InterfaceStrings) Less(i, j int) bool { return a[i].(string) < a[j].(string) }
-
-// Binary string search in slice
-// returns true if found and the index
-func GetSliceInterfaceIndex(ss []interface{}, s interface{}) (int, bool) {
-	if i := sort.Search(len(ss), func(i int) bool { return ss[i].(string) >= s.(string) }); i < len(ss) && ss[i] == s {
-		return i, true
-	}
-	return len(ss), false
-}