fixes #1636

app/models/post.rb

@@ -617,6 +617,12 @@ class Post < ActiveRecord::Base
       update_column(:pool_string, pool_string) unless new_record?
       pool.remove!(self)
     end
+
+    def remove_from_all_pools
+      pools.find_each do |pool|
+        pool.remove!(self)
+      end
+    end
   end
 
   module VoteMethods
@@ -823,6 +829,7 @@ class Post < ActiveRecord::Base
       update_children_on_destroy
       update_parent_on_destroy
       decrement_tag_post_counts
+      remove_from_all_pools
       destroy
     end
 

test/unit/post_test.rb

@@ -31,6 +31,14 @@ class PostTest < ActiveSupport::TestCase
         end
       end
 
+      should "remove the post from all pools" do
+        pool = FactoryGirl.create(:pool)
+        pool.add!(@post)
+        @post.expunge!
+        pool.reload
+        assert_equal("", pool.post_ids)
+      end
+
       should "destroy the record" do
         @post.expunge!
         assert_equal([], @post.errors.full_messages)