diff --git a/lib/hammer/atomic.ex b/lib/hammer/atomic.ex
index 0c67385..780b41c 100644
--- a/lib/hammer/atomic.ex
+++ b/lib/hammer/atomic.ex
@@ -186,8 +186,14 @@ defmodule Hammer.Atomic do
   end
 
   defp clean(config) do
-    table = config.table
+    case config.algorithm_module do
+      Hammer.Atomic.FixWindow -> clean_fix_window(config)
+      _ -> clean_bucket(config)
+    end
+  end
 
+  # FixWindow stores expires_at in milliseconds in slot 2
+  defp clean_fix_window(config) do
     now = now()
 
     :ets.foldl(
@@ -195,14 +201,35 @@ defmodule Hammer.Atomic do
         expires_at = :atomics.get(atomic, 2)
 
         if now - expires_at > config.key_older_than do
-          :ets.delete_object(table, term)
+          :ets.delete_object(config.table, term)
+          deleted + 1
+        else
+          deleted
+        end
+      end,
+      0,
+      config.table
+    )
+  end
+
+  # TokenBucket and LeakyBucket store last_update in seconds in slot 2
+  defp clean_bucket(config) do
+    now = System.system_time(:second)
+    older_than = now - div(config.key_older_than, 1000)
+
+    :ets.foldl(
+      fn {_key, atomic} = term, deleted ->
+        last_update = :atomics.get(atomic, 2)
+
+        if last_update < older_than do
+          :ets.delete_object(config.table, term)
           deleted + 1
         else
           deleted
         end
       end,
       0,
-      table
+      config.table
     )
   end
 
diff --git a/lib/hammer/ets/leaky_bucket.ex b/lib/hammer/ets/leaky_bucket.ex
index 224533c..c8b0122 100644
--- a/lib/hammer/ets/leaky_bucket.ex
+++ b/lib/hammer/ets/leaky_bucket.ex
@@ -165,8 +165,8 @@ defmodule Hammer.ETS.LeakyBucket do
   """
   @spec clean(config :: ETS.config()) :: non_neg_integer()
   def clean(config) do
-    now = ETS.now()
-    older_than = now - config.key_older_than
+    now = System.system_time(:second)
+    older_than = now - div(config.key_older_than, 1000)
 
     match_spec = [{{:_, :_, :"$1"}, [], [{:<, :"$1", {:const, older_than}}]}]
     :ets.select_delete(config.table, match_spec)
diff --git a/lib/hammer/ets/token_bucket.ex b/lib/hammer/ets/token_bucket.ex
index b2d1fa8..e06a5ee 100644
--- a/lib/hammer/ets/token_bucket.ex
+++ b/lib/hammer/ets/token_bucket.ex
@@ -165,8 +165,8 @@ defmodule Hammer.ETS.TokenBucket do
   """
   @spec clean(config :: ETS.config()) :: non_neg_integer()
   def clean(config) do
-    now = ETS.now()
-    older_than = now - config.key_older_than
+    now = System.system_time(:second)
+    older_than = now - div(config.key_older_than, 1000)
 
     match_spec = [{{:_, :_, :"$1"}, [], [{:<, :"$1", {:const, older_than}}]}]
     :ets.select_delete(config.table, match_spec)
diff --git a/test/hammer/atomic/clean_test.exs b/test/hammer/atomic/clean_test.exs
index 62c5f70..0ac3aef 100644
--- a/test/hammer/atomic/clean_test.exs
+++ b/test/hammer/atomic/clean_test.exs
@@ -51,7 +51,7 @@ defmodule Hammer.Atomic.CleanTest do
   end
 
   test "cleaning works for token bucket" do
-    start_supervised!({RateAtomicLimitTokenBucket, clean_period: 50, key_older_than: 10})
+    start_supervised!({RateAtomicLimitTokenBucket, clean_period: 100, key_older_than: 1000})
 
     key = "key"
     refill_rate = 1
@@ -68,7 +68,7 @@ defmodule Hammer.Atomic.CleanTest do
   end
 
   test "cleaning works for leaky bucket" do
-    start_supervised!({RateAtomicLimitLeakyBucket, clean_period: 50, key_older_than: 10})
+    start_supervised!({RateAtomicLimitLeakyBucket, clean_period: 100, key_older_than: 1000})
 
     key = "key"
     leak_rate = 1
diff --git a/test/hammer/ets/clean_test.exs b/test/hammer/ets/clean_test.exs
index 0ff462f..e945ff9 100644
--- a/test/hammer/ets/clean_test.exs
+++ b/test/hammer/ets/clean_test.exs
@@ -72,7 +72,7 @@ defmodule Hammer.ETS.CleanTest do
   end
 
   test "cleaning works for token bucket" do
-    start_supervised!({RateLimitTokenBucket, clean_period: 100})
+    start_supervised!({RateLimitTokenBucket, clean_period: 100, key_older_than: 1000})
 
     key = "key"
     refill_rate = 1
@@ -89,7 +89,7 @@ defmodule Hammer.ETS.CleanTest do
   end
 
   test "cleaning works for leaky bucket" do
-    start_supervised!({RateLimitLeakyBucket, clean_period: 100})
+    start_supervised!({RateLimitLeakyBucket, clean_period: 100, key_older_than: 1000})
 
     key = "key"
     leak_rate = 1