diff --git a/app/controllers/assets_controller.rb b/app/controllers/assets_controller.rb
index 1c56ef088..7c7ddbb1c 100644
--- a/app/controllers/assets_controller.rb
+++ b/app/controllers/assets_controller.rb
@@ -48,7 +48,7 @@ class AssetsController < ApplicationController
 
   def preview
     if @asset.is_image?
-      redirect_to @asset.presigned_url(:medium), status: 307
+      redirect_to @asset.url(:medium), status: 307
     else
       render_400
     end
diff --git a/app/helpers/reports_helper.rb b/app/helpers/reports_helper.rb
index 383f10b29..51b90e7a1 100644
--- a/app/helpers/reports_helper.rb
+++ b/app/helpers/reports_helper.rb
@@ -81,7 +81,7 @@ end
 def report_image_asset_url(asset)
   prefix = (ENV["PAPERCLIP_STORAGE"].present? && ENV["MAIL_SERVER_URL"].present? && ENV["PAPERCLIP_STORAGE"] == "filesystem") ? ENV["MAIL_SERVER_URL"] : ""
   prefix = (!prefix.empty? && !prefix.include?("http://") && !prefix.include?("https://")) ? "http://#{prefix}" : prefix
-  url = prefix + asset.presigned_url(:medium, time: 86_400)
+  url = prefix + asset.url(:medium, timeout: 86_400)
   image_tag(url)
 end
 
diff --git a/app/models/asset.rb b/app/models/asset.rb
index 8327e21bf..ec6566f86 100644
--- a/app/models/asset.rb
+++ b/app/models/asset.rb
@@ -215,23 +215,12 @@ class Asset < ActiveRecord::Base
   end
 
   def destroy
-    # Delete files from S3 (when updating an existing file, paperclip does
-    # this automatically, so this is not needed in such cases)
-    key = file.path[1..-1]
-    S3_BUCKET.object(key).delete
-    Rails.logger.info "Asset #{id} (original): Asset file "\
-         "successfully deleted from S3 (" + key.to_s + ')'
-    if (file_content_type =~ %r{^image\/}) == 0
-      file.options[:styles].each do |style, _|
-        key = file.path(style)[1..-1]
-        S3_BUCKET.object(key).delete
-        Rails.logger.info "Asset #{id} (" + style.to_s + '): Asset file '\
-         'successfully deleted from S3 (' + key.to_s + ')'
-      end
-    end
-
     report_elements.destroy_all
     asset_text_datum.destroy if asset_text_datum.present?
+
+    # Nullify needed to force paperclip file deletion
+    self.file = nil
+    save
     delete
   end
 
@@ -259,7 +248,16 @@ class Asset < ActiveRecord::Base
     end
   end
 
-  def presigned_url(style = :original, download: false, time: 30)
+  def url(style = :original, timeout: 30)
+    if file.is_stored_on_s3?
+      presigned_url(style, timeout: timeout)
+    else
+      file.url(style)
+    end
+  end
+
+  # When using S3 file upload, we can limit file accessibility with url signing
+  def presigned_url(style = :original, download: false, timeout: 30)
     if file.is_stored_on_s3?
       if download
         download_arg = 'attachment; filename=' + URI.escape(file_file_name)
@@ -271,12 +269,20 @@ class Asset < ActiveRecord::Base
       signer.presigned_url(:get_object,
         bucket: S3_BUCKET.name,
         key: file.path(style)[1..-1],
-        expires_in: time,
+        expires_in: timeout,
         # this response header forces object download
         response_content_disposition: download_arg)
     end
   end
 
+  def open
+    if file.is_stored_on_s3?
+      Kernel.open(presigned_url, "rb")
+    else
+      File.open(file.path, "rb")
+    end
+  end
+
   # Preserving attachments (on client-side) between failed validations (only usable for small/few files!)
   # Needs to be called before save method and view needs to have :file_content and :file_info hidden field
   # If file is an image, it can be viewed on front-end using @preview_cached with image_tag tag
diff --git a/app/utilities/protocols_exporter.rb b/app/utilities/protocols_exporter.rb
index e31aca1d1..6a1fa5129 100644
--- a/app/utilities/protocols_exporter.rb
+++ b/app/utilities/protocols_exporter.rb
@@ -53,11 +53,7 @@ module ProtocolsExporter
         asset_json["fileType"] = asset_json.delete("file_content_type")
 
         # Retrieve file contents
-        if asset.file.is_stored_on_s3?
-          file = open(asset.presigned_url, "rb")
-        else
-          file = File.open(asset.file.path, "rb")
-        end
+        file = asset.open
         asset_json["bytes"] = Base64.encode64(file.read)
         file.close