diff --git a/app/src/main/java/pl/szczodrzynski/edziennik/network/cookie/DumbCookie.kt b/app/src/main/java/pl/szczodrzynski/edziennik/network/cookie/DumbCookie.kt
index 53665332..ecd513b0 100644
--- a/app/src/main/java/pl/szczodrzynski/edziennik/network/cookie/DumbCookie.kt
+++ b/app/src/main/java/pl/szczodrzynski/edziennik/network/cookie/DumbCookie.kt
@@ -33,7 +33,10 @@ class DumbCookie(var cookie: Cookie) {
         cookie = Cookie.Builder()
                 .name(cookie.name())
                 .value(cookie.value())
-                .expiresAt(cookie.expiresAt())
+                .also {
+                    if (cookie.persistent())
+                        it.expiresAt(cookie.expiresAt())
+                }
                 .domain(cookie.domain())
                 .build()
     }
@@ -58,8 +61,6 @@ class DumbCookie(var cookie: Cookie) {
         return hash
     }
 
-    fun serialize(): Pair<String, String> {
-        val key = cookie.domain() + "|" + cookie.name()
-        return key to cookie.toString()
-    }
+    fun serializeKey() = cookie.domain() + "|" + cookie.name()
+    fun serialize() = serializeKey() to cookie.toString()
 }
diff --git a/app/src/main/java/pl/szczodrzynski/edziennik/network/cookie/DumbCookieJar.kt b/app/src/main/java/pl/szczodrzynski/edziennik/network/cookie/DumbCookieJar.kt
index 3bb9e0e5..945e16ea 100644
--- a/app/src/main/java/pl/szczodrzynski/edziennik/network/cookie/DumbCookieJar.kt
+++ b/app/src/main/java/pl/szczodrzynski/edziennik/network/cookie/DumbCookieJar.kt
@@ -30,10 +30,20 @@ class DumbCookieJar(
     private val sessionCookies = mutableSetOf<DumbCookie>()
 
     init {
+        val toRemove = mutableListOf<String>()
         prefs.all.forEach { (key, value) ->
             if (value !is String)
                 return@forEach
-            sessionCookies.add(DumbCookie.deserialize(key, value) ?: return@forEach)
+            val dc = DumbCookie.deserialize(key, value) ?: return@forEach
+            if (dc.cookie.expiresAt() > System.currentTimeMillis())
+                sessionCookies.add(dc)
+            else
+                toRemove.add(key)
+        }
+        prefs.edit {
+            for (key in toRemove) {
+                remove(key)
+            }
         }
     }
 
@@ -48,7 +58,14 @@ class DumbCookieJar(
         }
     }
     private fun delete(vararg toRemove: DumbCookie) {
-        sessionCookies.removeAll(toRemove)
+        sessionCookies.removeAll(toRemove.toSet())
+        prefs.edit {
+            for (dc in toRemove) {
+                val key = dc.serializeKey()
+                if (prefs.contains(key))
+                    remove(key)
+            }
+        }
     }
 
     override fun saveFromResponse(url: HttpUrl, cookies: MutableList<Cookie>) {
@@ -114,4 +131,11 @@ class DumbCookieJar(
         }
         delete(*toRemove.toTypedArray())
     }
+
+    fun clearAllDomains() {
+        sessionCookies.clear()
+        prefs.edit {
+            clear()
+        }
+    }
 }
diff --git a/app/src/main/java/pl/szczodrzynski/edziennik/ui/debug/LabPageFragment.kt b/app/src/main/java/pl/szczodrzynski/edziennik/ui/debug/LabPageFragment.kt
index 209d8e82..2e40eefc 100644
--- a/app/src/main/java/pl/szczodrzynski/edziennik/ui/debug/LabPageFragment.kt
+++ b/app/src/main/java/pl/szczodrzynski/edziennik/ui/debug/LabPageFragment.kt
@@ -179,6 +179,10 @@ class LabPageFragment : LazyFragment(), CoroutineScope {
             return@setOnChangeListener true
         }
 
+        b.clearCookies.onClick {
+            app.cookieJar.clearAllDomains()
+        }
+
         val colorSecondary = android.R.attr.textColorSecondary.resolveAttr(activity)
         startCoroutineTimer(500L, 300L) {
             val text = app.cookieJar.getAllDomains()
diff --git a/app/src/main/res/layout/lab_fragment.xml b/app/src/main/res/layout/lab_fragment.xml
index e41a66f2..af55e6f0 100644
--- a/app/src/main/res/layout/lab_fragment.xml
+++ b/app/src/main/res/layout/lab_fragment.xml
@@ -107,6 +107,14 @@
                 android:text="Reset event types"
                 android:textAllCaps="false" />
 
+            <Button
+                android:id="@+id/clearCookies"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="24dp"
+                android:text="Clear all cookies"
+                android:textAllCaps="false" />
+
             <TextView
                 android:id="@+id/cookies"
                 android:layout_width="match_parent"