diff --git a/libs/sofia-sip/libsofia-sip-ua/sresolv/sofia-resolv/sres_cache.h b/libs/sofia-sip/libsofia-sip-ua/sresolv/sofia-resolv/sres_cache.h
index b34260d51d..9eb8ab642b 100644
--- a/libs/sofia-sip/libsofia-sip-ua/sresolv/sofia-resolv/sres_cache.h
+++ b/libs/sofia-sip/libsofia-sip-ua/sresolv/sofia-resolv/sres_cache.h
@@ -90,6 +90,9 @@ SRESPUBFUN void sres_cache_free_answers(sres_cache_t *, sres_record_t **);
 /** Free and zero one record. */
 SRESPUBFUN void sres_cache_free_one(sres_cache_t *, sres_record_t *answer);
 
+/** Remove old records from cache.  */
+SRESPUBFUN void sres_cache_clean(sres_cache_t *cache, time_t now);
+
 /** Allocate a cache record */
 SRESPUBFUN
 sres_record_t *sres_cache_alloc_record(sres_cache_t *cache,
diff --git a/libs/sofia-sip/libsofia-sip-ua/sresolv/sres_cache.c b/libs/sofia-sip/libsofia-sip-ua/sresolv/sres_cache.c
index 40cc294a0c..f050d67496 100644
--- a/libs/sofia-sip/libsofia-sip-ua/sresolv/sres_cache.c
+++ b/libs/sofia-sip/libsofia-sip-ua/sresolv/sres_cache.c
@@ -437,7 +437,13 @@ sres_hash_key(const char *string)
   return result;
 }
 
-/** Remove entries from cache. */
+/** Remove old records from cache.
+ *
+ * Remove entries older than @a now from the cache.
+ *
+ * @param cache    pointer to DNS cache object
+ * @param now      remove older than this time
+ */
 void sres_cache_clean(sres_cache_t *cache, time_t now)
 {
   size_t i;