Switched to using proper Rake clobbering.

tasks/clobber.rake

@@ -1,2 +0,0 @@
-desc 'Remove all build products'
-task 'clobber'

tasks/gem.rake

@@ -1,4 +1,7 @@
 require 'rubygems/package_task'
+require 'rake/clean'
+
+CLOBBER.include('pkg')
 
 namespace :gem do
   GEM_SPEC = Gem::Specification.new do |s|
@@ -93,5 +96,3 @@ end
 
 desc 'Alias to gem:package'
 task 'gem' => 'gem:package'
-
-task 'clobber' => ['gem:clobber_package']

tasks/spec.rake

@@ -1,4 +1,7 @@
 require 'spec/rake/verify_rcov'
+require 'rake/clean'
+
+CLOBBER.include('coverage', 'specdoc')
 
 namespace :spec do
   Spec::Rake::SpecTask.new(:rcov) do |t|
@@ -79,5 +82,3 @@ else
   desc 'Alias to spec:all'
   task 'spec' => 'spec:all'
 end
-
-task 'clobber' => ['spec:clobber_rcov']

tasks/yard.rake

@@ -1,4 +1,8 @@
 require 'rake'
+require 'rake/clean'
+
+CLOBBER.include('doc', '.yardoc')
+CLOBBER.uniq!
 
 begin
   require 'yard'
@@ -10,13 +14,12 @@ begin
       yardoc.name = 'yard'
       yardoc.options = ['--verbose']
       yardoc.files = [
-        'lib/**/*.rb', 'ext/**/*.c', '-', 'README.md', 'CHANGELOG', 'LICENSE'
+        'lib/**/*.rb', 'ext/**/*.c', '-',
+        'README.md', 'CHANGELOG.md', 'LICENSE'
       ]
     end
   end
 
-  task 'clobber' => ['doc:clobber_yard']
-
   desc 'Alias to doc:yard'
   task 'doc' => 'doc:yard'
 rescue LoadError