diff --git a/lib/net/http/persistent.rb b/lib/net/http/persistent.rb
index e1fadbc..ad66842 100644
--- a/lib/net/http/persistent.rb
+++ b/lib/net/http/persistent.rb
@@ -1048,9 +1048,7 @@ def request_setup req_or_uri # :nodoc:
   # #shutdown when you are completely done making requests!
 
   def shutdown
-    @pool.available.shutdown do |http|
-      http.finish
-    end
+    @pool.shutdown { |http| http.finish }
   end
 
   ##
diff --git a/lib/net/http/persistent/pool.rb b/lib/net/http/persistent/pool.rb
index b88dd59..90fd92b 100644
--- a/lib/net/http/persistent/pool.rb
+++ b/lib/net/http/persistent/pool.rb
@@ -7,11 +7,11 @@ def initialize(options = {}, &block)
     super
 
     @available = Net::HTTP::Persistent::TimedStackMulti.new(@size, &block)
-    @key = :"current-#{@available.object_id}"
+    @key = "current-#{@available.object_id}"
   end
 
   def checkin net_http_args
-    stack = Thread.current[@key][net_http_args]
+    stack = Thread.current[@key][net_http_args] ||= []
 
     raise ConnectionPool::Error, 'no connections are checked out' if
       stack.empty?
@@ -26,8 +26,8 @@ def checkin net_http_args
   end
 
   def checkout net_http_args
-    stacks = Thread.current[@key] ||= Hash.new { |h, k| h[k] = [] }
-    stack  = stacks[net_http_args]
+    stacks = Thread.current[@key] ||= {}
+    stack  = stacks[net_http_args] ||= []
 
     if stack.empty? then
       conn = @available.pop connection_args: net_http_args
@@ -40,6 +40,10 @@ def checkout net_http_args
     conn
   end
 
+  def shutdown
+    Thread.current[@key] = nil
+    super
+  end
 end
 
 require 'net/http/persistent/timed_stack_multi'