diff --git a/src/GC/include/heap.hpp b/src/GC/include/heap.hpp
index be1b12e..0bd3d36 100644
--- a/src/GC/include/heap.hpp
+++ b/src/GC/include/heap.hpp
@@ -15,6 +15,8 @@
 #define FREE        (uint) 0x4
 #define COLLECT_ALL (uint) 0x7
 
+#define FREE_THRESH (uint) 20
+
 namespace GC {
 
   class Heap {
@@ -29,6 +31,8 @@ namespace GC {
 
     void collect();
     void sweep();
+    void free();
+    void free_overlap();
     // void compact();
     void mark(uintptr_t *start, const uintptr_t *end, std::vector<Chunk *> worklist);
     void print_line(Chunk *chunk);
diff --git a/src/GC/lib/heap.cpp b/src/GC/lib/heap.cpp
index f01233b..480fc3b 100644
--- a/src/GC/lib/heap.cpp
+++ b/src/GC/lib/heap.cpp
@@ -79,16 +79,44 @@ namespace GC {
 
     // compact();
 
+    free();
+
     // We shouldn't do this, since then m_freed_chunks doesnt' have any real purpose,
     // it should be used in alloc, it isn't if we delete *all* of its contentes
     // release free chunks
-    while (m_freed_chunks.size()) {
-      auto chunk_pointer = m_freed_chunks.back();
-      m_freed_chunks.pop_back();
-      delete chunk_pointer; // deletes chunk object, doesn't free memory to the OS
+    // while (m_freed_chunks.size()) {
+    //   auto chunk_pointer = m_freed_chunks.back();
+    //   m_freed_chunks.pop_back();
+    //   delete chunk_pointer; // deletes chunk object, doesn't free memory to the OS
+    // }
+  }
+
+  void Heap::free() {
+    if (m_freed_chunks.size() > FREE_THRESH) {
+      while (m_freed_chunks.size()) {
+        auto chunk = m_freed_chunks.back();
+        m_freed_chunks.pop_back();
+        delete chunk;
+      }
+    } else {
+      free_overlap();
     }
   }
 
+  void Heap::free_overlap() {
+    std::vector<Chunk *> filtered;
+    size_t i = 0;
+    filtered.push_back(m_freed_chunks.at(i++));
+    for (; i < m_freed_chunks.size(); i++) {
+      auto prev = filtered.back();
+      auto next = m_freed_chunks.at(i);
+      if (next->start > (prev->start + prev->size)) {
+        filtered.push_back(next);
+      }
+    }
+    m_freed_chunks.swap(filtered);
+  }
+
   void Heap::collect(uint flags) {
 
     cout << "DEBUG COLLECT\nFLAGS: ";
@@ -119,14 +147,18 @@ namespace GC {
       sweep();
     }
     
-    //release free chunks
     if (flags & FREE) {
-      while (m_freed_chunks.size()) {
-        auto chunk_pointer = m_freed_chunks.back();
-        m_freed_chunks.pop_back();
-        delete chunk_pointer; // deletes chunk object, doesn't free heap memory to the OS
-      }
+      free();
     }
+
+    //release free chunks
+    // if (flags & FREE) {
+    //   while (m_freed_chunks.size()) {
+    //     auto chunk_pointer = m_freed_chunks.back();
+    //     m_freed_chunks.pop_back();
+    //     delete chunk_pointer; // deletes chunk object, doesn't free heap memory to the OS
+    //   }
+    // }
   }
 
   // Not optimal for now, it doesn't have to loop over all objects
diff --git a/src/GC/todo.md b/src/GC/todo.md
index a327d71..3386d65 100644
--- a/src/GC/todo.md
+++ b/src/GC/todo.md
@@ -2,9 +2,8 @@
 
 ## Project
 
-Goal for next week (17/2):
-- Functioning garbage collector
-- Test it with valgrind
+Goal for next week (24/2):
+- Debug 
 
 ## GC TODO:
 - Merge to main branch
@@ -30,7 +29,7 @@ and evalutate the following:
         global stack_end = __builtin_frame_address(1)
 
     collect()
-        global stack_start = __builtin_frame_address(1)
+        local stack_start = __builtin_frame_address(1)
 
     sweep()
         for all addr in range(stack_end, stack_start)