diff --git a/services/shhext/requests.go b/services/shhext/requests.go
index ec537d0b0..11876e36f 100644
--- a/services/shhext/requests.go
+++ b/services/shhext/requests.go
@@ -22,11 +22,11 @@ type requestMeta struct {
 
 // NewRequestsRegistry creates instance of the RequestsRegistry and returns pointer to it.
 func NewRequestsRegistry(delay time.Duration) *RequestsRegistry {
-	return &RequestsRegistry{
-		delay:        delay,
-		uidToTopics:  map[common.Hash]common.Hash{},
-		byTopicsHash: map[common.Hash]requestMeta{},
+	r := &RequestsRegistry{
+		delay: delay,
 	}
+	r.Clear()
+	return r
 }
 
 // RequestsRegistry keeps map for all requests with timestamp when they were made.
@@ -73,6 +73,14 @@ func (r *RequestsRegistry) Unregister(uid common.Hash) {
 	}
 }
 
+// Clear recreates all structures used for caching requests.
+func (r *RequestsRegistry) Clear() {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.uidToTopics = map[common.Hash]common.Hash{}
+	r.byTopicsHash = map[common.Hash]requestMeta{}
+}
+
 // topicsToHash returns non-cryptographic hash of the topics.
 func topicsToHash(topics []whisper.TopicType) common.Hash {
 	hash := fnv.New32()
diff --git a/services/shhext/service.go b/services/shhext/service.go
index dd6302b97..c6c3b78f1 100644
--- a/services/shhext/service.go
+++ b/services/shhext/service.go
@@ -302,6 +302,7 @@ func (s *Service) Stop() error {
 	if s.config.EnableLastUsedMonitor {
 		s.lastUsedMonitor.Stop()
 	}
+	s.requestsRegistry.Clear()
 	s.envelopesMonitor.Stop()
 	s.mailMonitor.Stop()
 	return nil