diff --git a/caches/FileCache.php b/caches/FileCache.php
index bffdff3..ce8394e 100644
--- a/caches/FileCache.php
+++ b/caches/FileCache.php
@@ -31,8 +31,7 @@ class FileCache implements CacheInterface {
 		return false;
 	}
 
-	public function purgeCache(){
-		$cacheTimeLimit = time() - 86400; // 86400 -> 24h
+	public function purgeCache($duration){
 		$cachePath = $this->getPath();
 		if(file_exists($cachePath)){
 			$cacheIterator = new RecursiveIteratorIterator(
@@ -44,7 +43,7 @@ class FileCache implements CacheInterface {
 				if(in_array($cacheFile->getBasename(), array('.', '..')))
 					continue;
 				elseif($cacheFile->isFile()){
-					if(filemtime($cacheFile->getPathname()) < $cacheTimeLimit)
+					if(filemtime($cacheFile->getPathname()) < time() - $duration)
 						unlink($cacheFile->getPathname());
 				}
 			}
diff --git a/index.php b/index.php
index a20415d..599135a 100644
--- a/index.php
+++ b/index.php
@@ -131,7 +131,7 @@ try {
 		// Initialize cache
 		$cache = Cache::create('FileCache');
 		$cache->setPath(__DIR__ . '/cache');
-		$cache->purgeCache();
+		$cache->purgeCache(86400); // 24 hours
 		$cache->setParameters($params);
 
 		// Load cache & data
diff --git a/lib/CacheInterface.php b/lib/CacheInterface.php
index ab1066e..5753c0e 100644
--- a/lib/CacheInterface.php
+++ b/lib/CacheInterface.php
@@ -3,5 +3,5 @@ interface CacheInterface {
 	public function loadData();
 	public function saveData($datas);
 	public function getTime();
-	public function purgeCache();
+	public function purgeCache($duration);
 }