diff --git a/src/components/main/constellation.rs b/src/components/main/constellation.rs
index 31b6a5224cf8..555325b80c00 100644
--- a/src/components/main/constellation.rs
+++ b/src/components/main/constellation.rs
@@ -4,10 +4,9 @@
 
 use compositing::{CompositorChan, SetIds, SetLayerClipRect};
 
-use std::cell::Cell;
 use std::comm;
 use std::comm::Port;
-use std::task;
+use std::task::spawn_with;
 use geom::size::Size2D;
 use geom::rect::Rect;
 use gfx::opts::Opts;
@@ -258,32 +257,25 @@ impl Constellation {
                  profiler_chan: ProfilerChan)
                  -> ConstellationChan {
             
-        let opts = Cell::new((*opts).clone());
-
         let (constellation_port, constellation_chan) = special_stream!(ConstellationChan);
-        let constellation_port = Cell::new(constellation_port);
-
-        let compositor_chan = Cell::new(compositor_chan);
-        let constellation_chan_clone = Cell::new(constellation_chan.clone());
-
-        let resource_task = Cell::new(resource_task);
-        let image_cache_task = Cell::new(image_cache_task);
-        let profiler_chan = Cell::new(profiler_chan);
-
-        do task::spawn {
+        do spawn_with((constellation_port, constellation_chan.clone(),
+                       compositor_chan, resource_task, image_cache_task,
+                       profiler_chan, opts.clone()))
+            |(constellation_port, constellation_chan, compositor_chan, resource_task,
+              image_cache_task, profiler_chan, opts)| {
             let mut constellation = Constellation {
-                chan: constellation_chan_clone.take(),
-                request_port: constellation_port.take(),
-                compositor_chan: compositor_chan.take(),
-                resource_task: resource_task.take(),
-                image_cache_task: image_cache_task.take(),
+                chan: constellation_chan,
+                request_port: constellation_port,
+                compositor_chan: compositor_chan,
+                resource_task: resource_task,
+                image_cache_task: image_cache_task,
                 pipelines: HashMap::new(),
                 navigation_context: NavigationContext::new(),
                 next_pipeline_id: PipelineId(0),
                 pending_frames: ~[],
                 pending_sizes: HashMap::new(),
-                profiler_chan: profiler_chan.take(),
-                opts: opts.take(),
+                profiler_chan: profiler_chan,
+                opts: opts
             };
             constellation.run();
         }
@@ -730,9 +722,7 @@ impl Constellation {
                 None => {
                     // Add to_add to parent's children, if it is not the root
                     let parent = &to_add.parent;
-                    let to_add = Cell::new(to_add);
                     for parent in parent.iter() {
-                        let to_add = to_add.take();
                         let subpage_id = to_add.pipeline.subpage_id.expect("Constellation:
                             Child frame's subpage id is None. This should be impossible.");
                         let rect = self.pending_sizes.pop(&(parent.id, subpage_id));
diff --git a/src/components/script/script_task.rs b/src/components/script/script_task.rs
index 5ccdacad9be0..55311b5cf2a9 100644
--- a/src/components/script/script_task.rs
+++ b/src/components/script/script_task.rs
@@ -25,12 +25,11 @@ use servo_msg::constellation_msg::{PipelineId, SubpageId, RendererReadyMsg};
 use servo_msg::constellation_msg::{LoadIframeUrlMsg, IFrameSandboxed, IFrameUnsandboxed};
 use servo_msg::constellation_msg;
 
-use std::cell::Cell;
 use std::comm;
 use std::comm::{Port, SharedChan};
 use std::io::read_whole_file;
 use std::ptr;
-use std::task::{SingleThreaded, task};
+use std::task::spawn_with;
 use std::util::replace;
 use dom::window::TimerData;
 use geom::size::Size2D;
@@ -435,22 +434,19 @@ impl ScriptTask {
                                             resource_task: ResourceTask,
                                             image_cache_task: ImageCacheTask,
                                             initial_size: Future<Size2D<uint>>) {
-        let compositor = Cell::new(compositor);
-        let port = Cell::new(port);
-        let initial_size = Cell::new(initial_size);
-        // FIXME: rust#6399
-        let mut the_task = task();
-        the_task.sched_mode(SingleThreaded);
-        do spawn {
+        do spawn_with((compositor, layout_chan, port, chan, constellation_chan,
+                       resource_task, image_cache_task, initial_size))
+            |(compositor, layout_chan, port, chan, constellation_chan,
+                       resource_task, image_cache_task, initial_size)| {
             let script_task = ScriptTask::new(id,
-                                              @compositor.take() as @ScriptListener,
-                                              layout_chan.clone(),
-                                              port.take(),
-                                              chan.clone(),
-                                              constellation_chan.clone(),
-                                              resource_task.clone(),
-                                              image_cache_task.clone(),
-                                              initial_size.take());
+                @compositor as @ScriptListener,
+                layout_chan,
+                port,
+                chan,
+                constellation_chan,
+                resource_task,
+                image_cache_task,
+                initial_size);
             script_task.start();
         }
     }