diff --git a/lib/priv.h b/lib/priv.h
index 77c8978..422e1ef 100644
--- a/lib/priv.h
+++ b/lib/priv.h
@@ -30,6 +30,8 @@ typedef struct {
 } VALUE;
 
 TYC_TYPE value_type(VALUE v);
+bool     type_is_collectable(TYC_TYPE t);
+
 int32_t  value_integer(VALUE v);
 float    value_real(VALUE v);
 uint32_t value_idx(VALUE v);
@@ -63,6 +65,8 @@ TYC_RESULT stack_push_fp(Stack* s);
 TYC_RESULT stack_pop_fp(Stack* s);
 size_t     stack_fp_level(Stack* s);
 
+size_t     stack_collectable_array(Stack* s, VALUE** values);
+
 //
 // HEAP
 //
diff --git a/lib/stack.c b/lib/stack.c
index 96a4c84..46a9993 100644
--- a/lib/stack.c
+++ b/lib/stack.c
@@ -134,4 +134,15 @@ TYC_RESULT stack_pop_fp(Stack* s)
 size_t stack_fp_level(Stack* s)
 {
     return s->fp_n;
-}
\ No newline at end of file
+}
+
+size_t stack_collectable_array(Stack* s, VALUE** values)
+{
+    size_t j = 0;
+    *values = xmalloc(stack_len(s) * sizeof(VALUE));
+
+    for (size_t i = 0; i < s->stack_n; ++i)
+        if (type_is_collectable(s->stack[i].type))
+            (*values)[j++] = s->stack[i];
+    return j;
+}
diff --git a/lib/value.c b/lib/value.c
index 5685254..0c0670c 100644
--- a/lib/value.c
+++ b/lib/value.c
@@ -9,6 +9,11 @@ TYC_TYPE value_type(VALUE v)
     return v.type;
 }
 
+bool type_is_collectable(TYC_TYPE t)
+{
+    return t == TT_STRING || t == TT_ARRAY || t == TT_TABLE;
+}
+
 int32_t value_integer(VALUE v)
 {
 #ifdef CHECK_TYCHE_BUGS
diff --git a/test/tests.c b/test/tests.c
index cbd6bfa..91c5a41 100644
--- a/test/tests.c
+++ b/test/tests.c
@@ -4,6 +4,7 @@
 #include <math.h>
 #include <stdio.h>
 #include <string.h>
+#include <stdlib.h>
 
 #define EQ(a, b) (memcmp(a, b) == 0)
 
@@ -116,21 +117,28 @@ int main()
         stack_push(s, create_value_idx(TT_STRING, heap_add_string(h, "item2")));
         stack_push(s, create_value_idx(TT_STRING, heap_add_string(h, "item3")));
 
-        /*
+        size_t v_sz;
+        VALUE* v_idx;
+
         assert(heap_size(h) == 3);
-        heap_gc(h, s->stack, s->stack_n);
+        v_sz = stack_collectable_array(s, &v_idx);
+        heap_gc(h, v_idx, v_sz);
+        free(v_idx);
         assert(heap_size(h) == 3);
 
         stack_pop(s, NULL);
 
         assert(heap_size(h) == 3);
-        heap_gc(&h, s.stack, s.stack_n);
+        v_sz = stack_collectable_array(s, &v_idx);
+        heap_gc(h, v_idx, v_sz);
+        free(v_idx);
         assert(heap_size(h) == 2);
 
         stack_pop(s, NULL);
-        heap_gc(&h, s.stack, s.stack_n);
+        v_sz = stack_collectable_array(s, &v_idx);
+        heap_gc(h, v_idx, v_sz);
+        free(v_idx);
         assert(heap_size(h) == 1);
-         */
 
         heap_destroy(h);
         stack_destroy(s);