diff --git a/pool.go b/pool.go
index d5069ef..53471e2 100644
--- a/pool.go
+++ b/pool.go
@@ -74,7 +74,7 @@ func (p *Pool) monitorAndClear() {
 					break
 				}
 				n = i
-				w.stop()
+				w.task <- nil
 				idleWorkers[i] = nil
 				p.running--
 			}
@@ -118,7 +118,7 @@ func (p *Pool) Submit(task f) error {
 		return ErrPoolClosed
 	}
 	w := p.getWorker()
-	w.sendTask(task)
+	w.task <- task
 	return nil
 }
 
@@ -143,11 +143,12 @@ func (p *Pool) Release() error {
 		p.release <- sig{}
 		running := p.Running()
 		for i := 0; i < running; i++ {
-			p.getWorker().stop()
+			p.getWorker().task <- nil
 		}
 		for i := range p.workers {
 			p.workers[i] = nil
 		}
+		p.workers = nil
 	})
 	return nil
 }
@@ -157,7 +158,7 @@ func (p *Pool) ReSize(size int) {
 	if size < p.Cap() {
 		diff := p.Cap() - size
 		for i := 0; i < diff; i++ {
-			p.getWorker().stop()
+			p.getWorker().task <- nil
 		}
 	} else if size == p.Cap() {
 		return
diff --git a/pool_func.go b/pool_func.go
index b2ef61e..d99269f 100644
--- a/pool_func.go
+++ b/pool_func.go
@@ -75,7 +75,7 @@ func (p *PoolWithFunc) monitorAndClear() {
 					break
 				}
 				n = i
-				w.stop()
+				w.args <- nil
 				idleWorkers[i] = nil
 				p.running--
 			}
@@ -123,7 +123,7 @@ func (p *PoolWithFunc) Serve(args interface{}) error {
 		return ErrPoolClosed
 	}
 	w := p.getWorker()
-	w.sendTask(args)
+	w.args <- args
 	return nil
 }
 
@@ -148,11 +148,12 @@ func (p *PoolWithFunc) Release() error {
 		p.release <- sig{}
 		running := p.Running()
 		for i := 0; i < running; i++ {
-			p.getWorker().stop()
+			p.getWorker().args <- nil
 		}
 		for i := range p.workers {
 			p.workers[i] = nil
 		}
+		p.workers = nil
 	})
 	return nil
 }
@@ -162,7 +163,7 @@ func (p *PoolWithFunc) ReSize(size int) {
 	if size < p.Cap() {
 		diff := p.Cap() - size
 		for i := 0; i < diff; i++ {
-			p.getWorker().stop()
+			p.getWorker().args <- nil
 		}
 	} else if size == p.Cap() {
 		return
diff --git a/worker.go b/worker.go
index babb8af..9031f57 100644
--- a/worker.go
+++ b/worker.go
@@ -56,13 +56,3 @@ func (w *Worker) run() {
 		}
 	}()
 }
-
-// stop this worker.
-func (w *Worker) stop() {
-	w.sendTask(nil)
-}
-
-// sendTask sends a task to this worker.
-func (w *Worker) sendTask(task f) {
-	w.task <- task
-}
diff --git a/worker_func.go b/worker_func.go
index 6467bac..a3b5bb6 100644
--- a/worker_func.go
+++ b/worker_func.go
@@ -56,13 +56,3 @@ func (w *WorkerWithFunc) run() {
 		}
 	}()
 }
-
-// stop this worker.
-func (w *WorkerWithFunc) stop() {
-	w.sendTask(nil)
-}
-
-// sendTask sends a task to this worker.
-func (w *WorkerWithFunc) sendTask(args interface{}) {
-	w.args <- args
-}