diff --git a/zipserver/copy_handler.go b/zipserver/copy_handler.go
index b6d69d6..c81955c 100644
--- a/zipserver/copy_handler.go
+++ b/zipserver/copy_handler.go
@@ -87,13 +87,13 @@ func copyHandler(w http.ResponseWriter, r *http.Request) error {
 		storage, err := NewGcsStorage(config)
 
 		if storage == nil {
-			log.Fatal("Failed to create storage: ", err)
+			log.Fatal("Failed to create source (GCS) storage: ", err)
 		}
 
 		targetStorage, err := NewS3Storage(config)
 
 		if storage == nil {
-			log.Fatal("Failed to create storage: ", err)
+			log.Fatal("Failed to create target (S3) storage: ", err)
 		}
 
 		startTime := time.Now()
diff --git a/zipserver/mem_storage.go b/zipserver/mem_storage.go
index 671a933..f089e4a 100644
--- a/zipserver/mem_storage.go
+++ b/zipserver/mem_storage.go
@@ -1,5 +1,9 @@
 package zipserver
 
+// MemStorage implements Storage interface in memory, storing objects in a map.
+// This is used for the serving of a zip file over http. Keep in mind extracted
+// zips are stored forever, this should only be used for testing or one-off use
+
 import (
 	"bytes"
 	"context"
diff --git a/zipserver/s3_storage.go b/zipserver/s3_storage.go
index 86b15da..d3afb4f 100644
--- a/zipserver/s3_storage.go
+++ b/zipserver/s3_storage.go
@@ -102,3 +102,18 @@ func (c *S3Storage) HeadFile(ctx context.Context, bucket, key string) (url.Value
 
 	return out, nil
 }
+
+func (c *S3Storage) DeleteFile(ctx context.Context, bucket, key string) error {
+	svc := s3.New(c.Session)
+	input := &s3.DeleteObjectInput{
+		Bucket: aws.String(bucket),
+		Key:    aws.String(key),
+	}
+
+	_, err := svc.DeleteObjectWithContext(ctx, input)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}