diff --git a/src/free.c b/src/free.c
index 266faad8..3fdb35aa 100644
--- a/src/free.c
+++ b/src/free.c
@@ -220,7 +220,7 @@ static void mi_decl_noinline mi_free_try_collect_mt(mi_page_t* page, mi_block_t*
   if (mi_page_all_free(page))
   {
     // first remove it from the abandoned pages in the arena (if mapped, this waits for any readers to finish)
-      _mi_arenas_page_unabandon(page);
+    _mi_arenas_page_unabandon(page);
     // we can free the page directly
     _mi_arenas_page_free(page);
     return;
@@ -244,8 +244,9 @@ static void mi_decl_noinline mi_free_try_collect_mt(mi_page_t* page, mi_block_t*
     // can we reclaim?
     if (heap != NULL && heap->allow_page_reclaim) {
       if (heap == page->heap ||                  // only reclaim if we were the originating heap,
-          (reclaim_on_free == 1 &&               // OR if the reclaim option across heaps is enabled
+          (reclaim_on_free == 1 &&               // OR if the reclaim across heaps is allowed
            !mi_page_is_used_at_frac(page, 8) &&  //    and the page is not too full
+           !heap->tld->is_in_threadpool &&       //    and not part of a threadpool
            _mi_arena_memid_is_suitable(page->memid, heap->exclusive_arena))  // and the memory is suitable    
          )
       {
diff --git a/src/heap.c b/src/heap.c
index 5ac79996..daad8afc 100644
--- a/src/heap.c
+++ b/src/heap.c
@@ -181,10 +181,10 @@ void _mi_heap_init(mi_heap_t* heap, mi_arena_id_t arena_id, bool allow_destroy,
   heap->tag        = heap_tag;
   if (heap->tld->is_in_threadpool) {
     // if we run as part of a thread pool it is better to not arbitrarily reclaim abandoned pages into our heap.
-    heap->allow_page_reclaim = false;
-    // .. but abandoning is good in this case: quarter the full page retain (possibly to 0)
+    // this is checked in `free.c:mi_free_try_collect_mt`
+    // .. but abandoning is good in this case: halve the full page retain (possibly to 0)
     // (so blocked threads do not hold on to too much memory)
-    if (heap->page_full_retain >= 0) {
+    if (heap->page_full_retain > 0) {
       heap->page_full_retain = heap->page_full_retain / 4;
     }
   }
diff --git a/src/page.c b/src/page.c
index 2a51bea6..b3dabb41 100644
--- a/src/page.c
+++ b/src/page.c
@@ -279,7 +279,7 @@ void _mi_page_abandon(mi_page_t* page, mi_page_queue_t* pq) {
   else {
     mi_page_queue_remove(pq, page);
     mi_heap_t* heap = page->heap;
-    mi_page_set_heap(page, NULL);  
+    mi_page_set_heap(page, NULL);
     page->heap = heap; // dont set heap to NULL so we can reclaim_on_free within the same heap
     _mi_arenas_page_abandon(page, heap->tld);
     _mi_arenas_collect(false, false, heap->tld); // allow purging
@@ -358,11 +358,11 @@ static void mi_page_to_full(mi_page_t* page, mi_page_queue_t* pq) {
 
   mi_heap_t* heap = mi_page_heap(page);
   if (heap->allow_page_abandon) {
-    // abandon full pages
+    // abandon full pages (this is the usual case in order to allow for sharing of memory between heaps)
     _mi_page_abandon(page, pq);
   }
   else if (!mi_page_is_in_full(page)) {
-    // put full pages in a heap local queue
+    // put full pages in a heap local queue (this is for heaps that cannot abandon, for example, if the heap can be destroyed)
     mi_page_queue_enqueue_from(&mi_page_heap(page)->pages[MI_BIN_FULL], pq, page);
     _mi_page_free_collect(page, false);  // try to collect right away in case another thread freed just before MI_USE_DELAYED_FREE was set
   }