diff --git a/crates/polars-io/src/cloud/adaptors.rs b/crates/polars-io/src/cloud/adaptors.rs
index 6037216b2a0d9..09dc5d3eeaa8d 100644
--- a/crates/polars-io/src/cloud/adaptors.rs
+++ b/crates/polars-io/src/cloud/adaptors.rs
@@ -148,7 +148,7 @@ pub struct CloudWriter {
     // The Tokio runtime which the writer uses internally.
     runtime: tokio::runtime::Runtime,
     // Internal writer, constructed at creation
-    writer: std::sync::Mutex<Box<dyn AsyncWrite + Send + Unpin>>,
+    writer: Box<dyn AsyncWrite + Send + Unpin>,
 }
 
 impl CloudWriter {
@@ -198,11 +198,10 @@ impl CloudWriter {
         path: &Path,
     ) -> object_store::Result<(
         MultipartId,
-        std::sync::Mutex<Box<dyn AsyncWrite + Send + Unpin>>,
+        Box<dyn AsyncWrite + Send + Unpin>,
     )> {
-        let (multipart_id, async_s3_writer) = object_store.put_multipart(path).await?;
-        let sync_s3_uploader = std::sync::Mutex::new(async_s3_writer);
-        Ok((multipart_id, sync_s3_uploader))
+        let (multipart_id, s3_writer) = object_store.put_multipart(path).await?;
+        Ok((multipart_id, s3_writer))
     }
 
     fn abort(&self) {
@@ -216,8 +215,7 @@ impl CloudWriter {
 
 impl std::io::Write for CloudWriter {
     fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
-        let mut writer = self.writer.lock().unwrap();
-        let res = self.runtime.block_on(writer.write(buf));
+        let res = self.runtime.block_on(self.writer.write(buf));
         if res.is_err() {
             self.abort();
         }
@@ -225,8 +223,7 @@ impl std::io::Write for CloudWriter {
     }
 
     fn flush(&mut self) -> std::io::Result<()> {
-        let mut writer = self.writer.lock().unwrap();
-        let res = self.runtime.block_on(writer.flush());
+        let res = self.runtime.block_on(self.writer.flush());
         if res.is_err() {
             self.abort();
         }
@@ -236,8 +233,7 @@ impl std::io::Write for CloudWriter {
 
 impl Drop for CloudWriter {
     fn drop(&mut self) {
-        let mut writer = self.writer.lock().unwrap();
-        let _ = self.runtime.block_on(writer.shutdown());
+        let _ = self.runtime.block_on(self.writer.shutdown());
     }
 }
 
diff --git a/crates/polars-pipe/src/executors/sinks/file_sink.rs b/crates/polars-pipe/src/executors/sinks/file_sink.rs
index 1114bc5fbf8cf..ce1326379141e 100644
--- a/crates/polars-pipe/src/executors/sinks/file_sink.rs
+++ b/crates/polars-pipe/src/executors/sinks/file_sink.rs
@@ -110,7 +110,7 @@ impl ParquetCloudSink {
             .set_parallel(false)
             .batched(schema)?;
 
-        let writer = Box::new(writer) as Box<dyn SinkWriter + Send + Sync>;
+        let writer = Box::new(writer) as Box<dyn SinkWriter + Send>;
 
         let morsels_per_sink = morsels_per_sink();
         let backpressure = morsels_per_sink * 2;
@@ -164,7 +164,7 @@ impl IpcSink {
 #[cfg(any(feature = "parquet", feature = "ipc"))]
 fn init_writer_thread(
     receiver: Receiver<Option<DataChunk>>,
-    mut writer: Box<dyn SinkWriter + Send + Sync>,
+    mut writer: Box<dyn SinkWriter + Send>,
     maintain_order: bool,
     // this is used to determine when a batch of chunks should be written to disk
     // all chunks per push should be collected to determine in which order they should
diff --git a/crates/polars-pipe/src/executors/sinks/groupby/aggregates/convert.rs b/crates/polars-pipe/src/executors/sinks/groupby/aggregates/convert.rs
index eeeec8f148798..0acf4d434c66f 100644
--- a/crates/polars-pipe/src/executors/sinks/groupby/aggregates/convert.rs
+++ b/crates/polars-pipe/src/executors/sinks/groupby/aggregates/convert.rs
@@ -107,9 +107,9 @@ pub fn can_convert_to_hash_agg(
 }
 
 /// # Returns:
-///     - input_dtype: dtype that goes into the agg expression
-///     - physical expr: physical expression that produces the input of the aggregation
-///     - aggregation function: the aggregation function
+///  - input_dtype: dtype that goes into the agg expression
+///  - physical expr: physical expression that produces the input of the aggregation
+///  - aggregation function: the aggregation function
 pub(crate) fn convert_to_hash_agg<F>(
     node: Node,
     expr_arena: &Arena<AExpr>,