diff --git a/hardware/Rakefile b/hardware/Rakefile
index f55626a..39d2b9c 100644
--- a/hardware/Rakefile
+++ b/hardware/Rakefile
@@ -41,8 +41,9 @@ desc "main building task"
 task :default => [:version,:print,:notes,:photo,:gerber]
 
 desc "create release file"
-task :release => "hardware-release_v#{version}.tar.gz"
-CLOBBER.include("hardware-release_v#{version}.tar.gz")
+release = "hardware-release_v#{version}.tar.gz"
+task :release => release
+CLOBBER.include(release) if File.exist? release
 
 desc "set version in schematic and layout"
 task :version => targets.collect{|target| [target[:vsch],target[:vpcb]]}.flatten
@@ -146,7 +147,7 @@ def bom2(schematic, attributes)
   end
   return to_return
 end
-CLEAN.include("attribs")
+CLEAN.include("attribs",:force)
 
 # ===============
 # file generation