diff --git a/examples/custom_shader/src/scene.rs b/examples/custom_shader/src/scene.rs
index 88f72970..d5515e49 100644
--- a/examples/custom_shader/src/scene.rs
+++ b/examples/custom_shader/src/scene.rs
@@ -128,16 +128,7 @@ impl Primitive {
 }
 
 impl shader::Primitive for Primitive {
-    type Renderer = Pipeline;
-
-    fn initialize(
-        &self,
-        device: &wgpu::Device,
-        queue: &wgpu::Queue,
-        format: wgpu::TextureFormat,
-    ) -> Pipeline {
-        Pipeline::new(device, queue, format)
-    }
+    type Pipeline = Pipeline;
 
     fn prepare(
         &self,
@@ -183,3 +174,13 @@ fn rnd_origin() -> Vec3 {
         rand::thread_rng().gen_range(-4.0..2.0),
     )
 }
+
+impl shader::Pipeline for Pipeline {
+    fn new(
+        device: &wgpu::Device,
+        queue: &wgpu::Queue,
+        format: wgpu::TextureFormat,
+    ) -> Pipeline {
+        Self::new(device, queue, format)
+    }
+}
diff --git a/wgpu/src/engine.rs b/wgpu/src/engine.rs
index 4bc30b7f..d86499eb 100644
--- a/wgpu/src/engine.rs
+++ b/wgpu/src/engine.rs
@@ -66,4 +66,13 @@ impl Engine {
             &self._shell,
         )
     }
+
+    pub fn trim(&mut self) {
+        self.text_pipeline.trim();
+
+        self.primitive_storage
+            .write()
+            .expect("primitive storage should be writable")
+            .trim();
+    }
 }
diff --git a/wgpu/src/lib.rs b/wgpu/src/lib.rs
index 8f2faa62..977a3add 100644
--- a/wgpu/src/lib.rs
+++ b/wgpu/src/lib.rs
@@ -149,8 +149,8 @@ impl Renderer {
         self.triangle.trim();
         self.text.trim();
 
-        // TODO: Move to runtime!
-        self.engine.text_pipeline.trim();
+        // TODO: Provide window id (?)
+        self.engine.trim();
 
         #[cfg(any(feature = "svg", feature = "image"))]
         {
diff --git a/wgpu/src/primitive.rs b/wgpu/src/primitive.rs
index cb2c02c7..4c18bb6a 100644
--- a/wgpu/src/primitive.rs
+++ b/wgpu/src/primitive.rs
@@ -19,23 +19,12 @@ pub trait Primitive: Debug + MaybeSend + MaybeSync + 'static {
     ///
     /// All instances of this [`Primitive`] type will share the same
     /// [`Renderer`].
-    type Renderer: MaybeSend + MaybeSync;
-
-    /// Initializes the [`Renderer`](Self::Renderer) of the [`Primitive`].
-    ///
-    /// This will only be called once, when the first [`Primitive`] of this kind
-    /// is encountered.
-    fn initialize(
-        &self,
-        device: &wgpu::Device,
-        queue: &wgpu::Queue,
-        format: wgpu::TextureFormat,
-    ) -> Self::Renderer;
+    type Pipeline: Pipeline + MaybeSend + MaybeSync;
 
     /// Processes the [`Primitive`], allowing for GPU buffer allocation.
     fn prepare(
         &self,
-        renderer: &mut Self::Renderer,
+        pipeline: &mut Self::Pipeline,
         device: &wgpu::Device,
         queue: &wgpu::Queue,
         bounds: &Rectangle,
@@ -57,7 +46,7 @@ pub trait Primitive: Debug + MaybeSend + MaybeSync + 'static {
     /// By default, it does nothing and returns `false`.
     fn draw(
         &self,
-        _renderer: &Self::Renderer,
+        _pipeline: &Self::Pipeline,
         _render_pass: &mut wgpu::RenderPass<'_>,
     ) -> bool {
         false
@@ -70,7 +59,7 @@ pub trait Primitive: Debug + MaybeSend + MaybeSync + 'static {
     /// By default, it does nothing.
     fn render(
         &self,
-        _renderer: &Self::Renderer,
+        _pipeline: &Self::Pipeline,
         _encoder: &mut wgpu::CommandEncoder,
         _target: &wgpu::TextureView,
         _clip_bounds: &Rectangle<u32>,
@@ -78,6 +67,26 @@ pub trait Primitive: Debug + MaybeSend + MaybeSync + 'static {
     }
 }
 
+/// The pipeline of a graphics [`Primitive`].
+pub trait Pipeline: Any + MaybeSend + MaybeSync {
+    /// Creates the [`Pipeline`] of a [`Primitive`].
+    ///
+    /// This will only be called once, when the first [`Primitive`] with this kind
+    /// of [`Pipeline`] is encountered.
+    fn new(
+        device: &wgpu::Device,
+        queue: &wgpu::Queue,
+        format: wgpu::TextureFormat,
+    ) -> Self
+    where
+        Self: Sized;
+
+    /// Trims any cached data in the [`Pipeline`].
+    ///
+    /// This will normally be called at the end of a frame.
+    fn trim(&mut self) {}
+}
+
 pub(crate) trait Stored:
     Debug + MaybeSend + MaybeSync + 'static
 {
@@ -122,15 +131,13 @@ impl<P: Primitive> Stored for BlackBox<P> {
         viewport: &Viewport,
     ) {
         if !storage.has::<P>() {
-            storage.store::<P, _>(
-                self.primitive.initialize(device, queue, format),
-            );
+            storage.store::<P, _>(P::Pipeline::new(device, queue, format));
         }
 
         let renderer = storage
             .get_mut::<P>()
             .expect("renderer should be initialized")
-            .downcast_mut::<P::Renderer>()
+            .downcast_mut::<P::Pipeline>()
             .expect("renderer should have the proper type");
 
         self.primitive
@@ -145,7 +152,7 @@ impl<P: Primitive> Stored for BlackBox<P> {
         let renderer = storage
             .get::<P>()
             .expect("renderer should be initialized")
-            .downcast_ref::<P::Renderer>()
+            .downcast_ref::<P::Pipeline>()
             .expect("renderer should have the proper type");
 
         self.primitive.draw(renderer, render_pass)
@@ -161,7 +168,7 @@ impl<P: Primitive> Stored for BlackBox<P> {
         let renderer = storage
             .get::<P>()
             .expect("renderer should be initialized")
-            .downcast_ref::<P::Renderer>()
+            .downcast_ref::<P::Pipeline>()
             .expect("renderer should have the proper type");
 
         self.primitive
@@ -198,7 +205,7 @@ pub trait Renderer: core::Renderer {
 /// Stores custom, user-provided types.
 #[derive(Default)]
 pub struct Storage {
-    pipelines: FxHashMap<TypeId, Box<dyn AnyConcurrent>>,
+    pipelines: FxHashMap<TypeId, Box<dyn Pipeline>>,
 }
 
 impl Storage {
@@ -208,11 +215,8 @@ impl Storage {
     }
 
     /// Inserts the data `T` in to [`Storage`].
-    pub fn store<T: 'static, D: Any + MaybeSend + MaybeSync>(
-        &mut self,
-        data: D,
-    ) {
-        let _ = self.pipelines.insert(TypeId::of::<T>(), Box::new(data));
+    pub fn store<T: 'static, P: Pipeline>(&mut self, pipeline: P) {
+        let _ = self.pipelines.insert(TypeId::of::<T>(), Box::new(pipeline));
     }
 
     /// Returns a reference to the data with type `T` if it exists in [`Storage`].
@@ -228,8 +232,11 @@ impl Storage {
             .get_mut(&TypeId::of::<T>())
             .map(|pipeline| pipeline.as_mut() as &mut dyn Any)
     }
+
+    /// Trims the cache of all the pipelines in the [`Storage`].
+    pub fn trim(&mut self) {
+        for pipeline in self.pipelines.values_mut() {
+            pipeline.trim();
+        }
+    }
 }
-
-trait AnyConcurrent: Any + MaybeSend + MaybeSync {}
-
-impl<T> AnyConcurrent for T where T: Any + MaybeSend + MaybeSync {}
diff --git a/widget/src/shader.rs b/widget/src/shader.rs
index 7ce06964..bd05504e 100644
--- a/widget/src/shader.rs
+++ b/widget/src/shader.rs
@@ -16,7 +16,7 @@ use std::marker::PhantomData;
 
 pub use crate::Action;
 pub use crate::graphics::Viewport;
-pub use primitive::{Primitive, Storage};
+pub use primitive::{Pipeline, Primitive, Storage};
 
 /// A widget which can render custom shaders with Iced's `wgpu` backend.
 ///