diff --git a/benchmark/each_bang_bm.rb b/benchmark/array_each_bang_bm.rb
similarity index 99%
rename from benchmark/each_bang_bm.rb
rename to benchmark/array_each_bang_bm.rb
index 3670529..f4d840e 100644
--- a/benchmark/each_bang_bm.rb
+++ b/benchmark/array_each_bang_bm.rb
@@ -13,7 +13,6 @@ class Thing; end
 puts '----------------------'
 
 arr = Array.new(100) { Thing.new }
-line = ''
 
 arr.each do |el|
   GC.start
diff --git a/benchmark/each_slice_bang_bm.rb b/benchmark/each_slice_bang_bm.rb
index 154d78d..318c4cc 100644
--- a/benchmark/each_slice_bang_bm.rb
+++ b/benchmark/each_slice_bang_bm.rb
@@ -15,7 +15,6 @@ class Thing; end
 puts '----------------------'
 
 arr = Array.new(100) { Thing.new }
-line = ''
 
 arr.each_slice(slize_size) do |slice|
   GC.start
diff --git a/benchmark/hash_each_bang_bm.rb b/benchmark/hash_each_bang_bm.rb
new file mode 100644
index 0000000..e6863d4
--- /dev/null
+++ b/benchmark/hash_each_bang_bm.rb
@@ -0,0 +1,104 @@
+require 'benchmark'
+require_relative '../lib/hyper_iterator'
+
+class Key; end
+class Val; end
+
+puts '---------------------------------------------------------'
+puts '------------------------- each! -------------------------'
+
+puts '---------------------------------------------------------'
+puts '------------------ Garbage Collection -------------------'
+
+puts 'Hash#each'
+puts '----------------------'
+
+hash = {}
+100.times do
+  hash[Key.new] = Val.new
+end
+
+hash.each do |_|
+  GC.start
+  print ObjectSpace.each_object(Key).count
+  print ' '
+  print ObjectSpace.each_object(Val).count
+  print ' '
+end
+
+puts
+puts
+
+puts 'Hash#each!'
+puts '----------------------'
+
+hash = {}
+100.times do
+  hash[Key.new] = Val.new
+end
+
+hash.each! do |_|
+  GC.start
+  print ObjectSpace.each_object(Key).count
+  print ' '
+  print ObjectSpace.each_object(Val).count
+  print ' '
+end
+
+puts
+
+puts '---------------------------------------------------------'
+puts '-------------------- Objects Created --------------------'
+
+
+GC.disable
+hash = {}
+100.times do
+  hash[Key.new] = Val.new
+end
+
+before = ObjectSpace.count_objects
+hash.each do |_|
+end
+after = ObjectSpace.count_objects
+
+puts 'Hash#each'
+puts '----------------------'
+puts "# of arrays: %d" % (after[:T_ARRAY] - before[:T_ARRAY])
+puts "# of nodes: %d" % (after[:T_NODE] - before[:T_NODE])
+
+puts
+
+hash = {}
+100.times do
+  hash[Key.new] = Val.new
+end
+
+before = ObjectSpace.count_objects
+hash.each! do |el|
+end
+after = ObjectSpace.count_objects
+
+puts 'Hash#each!'
+puts '----------------------'
+puts "# of arrays: %d" % (after[:T_ARRAY] - before[:T_ARRAY])
+puts "# of nodes: %d" % (after[:T_NODE] - before[:T_NODE])
+
+puts '---------------------------------------------------------'
+puts '--------------- Execution Time Comparison ---------------'
+
+GC.enable
+n = 10
+hash = {}
+10_000.times do
+  hash[Key.new] = Val.new
+end
+
+Benchmark.bmbm(7) do |x|
+  x.report('each!') { n.times { hash.each! { |el| nil } } }
+  x.report('each')  { n.times { hash.each  { |el| nil } } }
+end
+
+puts '---------------------------------------------------------'
+
+puts
\ No newline at end of file
diff --git a/benchmark/memory_bm/each.rb b/benchmark/memory_bm/array_each.rb
similarity index 100%
rename from benchmark/memory_bm/each.rb
rename to benchmark/memory_bm/array_each.rb
diff --git a/benchmark/memory_bm/each_bang.rb b/benchmark/memory_bm/array_each_bang.rb
similarity index 100%
rename from benchmark/memory_bm/each_bang.rb
rename to benchmark/memory_bm/array_each_bang.rb
diff --git a/benchmark/memory_bm/hash_each.rb b/benchmark/memory_bm/hash_each.rb
new file mode 100644
index 0000000..9a9b29d
--- /dev/null
+++ b/benchmark/memory_bm/hash_each.rb
@@ -0,0 +1,34 @@
+require 'benchmark'
+require_relative '../../lib/hyper_iterator'
+$stdout.sync = true
+
+puts
+puts '----------------- Hash#each -----------------'
+puts '#i    user      system      total       real'
+
+base_hash = {}
+1000.times { |i| base_hash["k#{i}"] = '-' * 10 }
+hashes = [base_hash]
+
+i = 0
+while true
+  print "#{i} "
+  hash = {}
+  report = Benchmark.measure do
+    hashes[i].each do |k, v|
+      hash[k.dup] = v.dup
+    end
+
+    # Try to use this line and see how many more iterations you can get
+    # Remember to uncomment line#24 as well.
+    # You need to pop the array so the reference goes away.
+    # arrs[0].each! { |el| arr << el.dup }
+  end
+
+  # Uncomment this to use with the above line#22
+  # arrs.pop
+
+  puts report
+  hashes << hash
+  i += 1
+end
diff --git a/benchmark/memory_bm/hash_each_bang.rb b/benchmark/memory_bm/hash_each_bang.rb
new file mode 100644
index 0000000..1e6752c
--- /dev/null
+++ b/benchmark/memory_bm/hash_each_bang.rb
@@ -0,0 +1,34 @@
+require 'benchmark'
+require_relative '../../lib/hyper_iterator'
+$stdout.sync = true
+
+puts
+puts '----------------- Hash#each! -----------------'
+puts '#i    user      system      total       real'
+
+base_hash = {}
+1000.times { |i| base_hash["k#{i}"] = '-' * 10 }
+hashes = [base_hash]
+
+i = 0
+while true
+  print "#{i} "
+  hash = {}
+  report = Benchmark.measure do
+    hashes[i].each! do |k, v|
+      hash[k.dup] = v.dup
+    end
+
+    # Try to use this line and see how many more iterations you can get
+    # Remember to uncomment line#24 as well.
+    # You need to pop the array so the reference goes away.
+    # arrs[0].each! { |el| arr << el.dup }
+  end
+
+  # Uncomment this to use with the above line#22
+  # arrs.pop
+
+  puts report
+  hashes << hash
+  i += 1
+end
diff --git a/bin/bm b/bin/bm
index df759c6..c4440eb 100755
--- a/bin/bm
+++ b/bin/bm
@@ -2,11 +2,14 @@
 
 docker_command="docker run -m=4m -v `pwd`:`pwd` -w `pwd` hyper_iterator ruby ./benchmark/memory_bm"
 if [ "$1" = "each!" ] || [ "$1" = 1 ]; then
-  eval "$docker_command/each.rb"
-  eval "$docker_command/each_bang.rb"
+  eval "$docker_command/array_each.rb"
+  eval "$docker_command/array_each_bang.rb"
 elif [ "$1" = "each_slice!" ] || [ "$1" = 2 ]; then
   eval "$docker_command/each_slice.rb"
   eval "$docker_command/each_slice_bang.rb"
+elif [ "$1" = 3 ]; then
+  eval "$docker_command/hash_each.rb"
+  eval "$docker_command/hash_each_bang.rb"
 else
   echo 'Please specify method for benchmarking. You can choose anyone from below:'
   echo '1. each!'
diff --git a/lib/hyper_iterator.rb b/lib/hyper_iterator.rb
index 077d54a..232395d 100644
--- a/lib/hyper_iterator.rb
+++ b/lib/hyper_iterator.rb
@@ -1,5 +1,6 @@
 require_relative "./hyper_iterator/version"
 require_relative "./iterators/each_bang"
+require_relative "./iterators/hash_each_bang"
 require_relative "./iterators/each_slice_bang"
 
 module HyperIterator
@@ -14,5 +15,5 @@ def self.each!(iterable)
 end
 
 Array.include HyperIterator::EachBang
-Hash.include HyperIterator::EachBang
+Hash.include HyperIterator::HashEachBang
 Array.include HyperIterator
\ No newline at end of file
diff --git a/lib/iterators/hash_each_bang.rb b/lib/iterators/hash_each_bang.rb
new file mode 100644
index 0000000..c1f8980
--- /dev/null
+++ b/lib/iterators/hash_each_bang.rb
@@ -0,0 +1,11 @@
+module HyperIterator
+  module HashEachBang
+    def each!
+      each do |pair|
+        yield pair
+        self[pair[0]] = nil
+      end
+      nil
+    end
+  end
+end
\ No newline at end of file
diff --git a/test/iterators/hash_each_bang_test.rb b/test/iterators/hash_each_bang_test.rb
index 94ae383..d0eb841 100644
--- a/test/iterators/hash_each_bang_test.rb
+++ b/test/iterators/hash_each_bang_test.rb
@@ -23,9 +23,9 @@ def test_that_it_yield_block
     assert vals == ord_range
   end
 
-  def test_that_it_remove_elements_from_array_on_the_fly
+  def test_that_it_sets_all_values_to_nil_on_the_fly
     @hash.each! {}
-    assert @hash.count == 0
+    assert @hash.values.all?(&:nil?)
   end
 
   def test_that_it_returns_nil
@@ -83,6 +83,6 @@ def test_that_it_can_use_class_method
 
     assert keys_1 == keys_2
     assert vals_1 == vals_2
-    assert hash_2.empty?
+    assert hash_2.values.all?(&:nil?)
   end
 end