diff --git a/include/bitcoin/network/memory.hpp b/include/bitcoin/network/memory.hpp
index 7cdf774e1..588654fba 100644
--- a/include/bitcoin/network/memory.hpp
+++ b/include/bitcoin/network/memory.hpp
@@ -34,7 +34,8 @@ class BCT_API memory
     virtual arena* get_arena() NOEXCEPT = 0;
 };
 
-/// Default tracked memory implementation (untracked).
+/// Default implementation of a thread safe arena container.
+/// This returns the default_arena, which passes through to new/delete.
 class BCT_API default_memory final
   : public memory
 {
diff --git a/src/messages/block.cpp b/src/messages/block.cpp
index 656f45a00..607495aea 100644
--- a/src/messages/block.cpp
+++ b/src/messages/block.cpp
@@ -33,7 +33,6 @@ namespace messages {
 
 using namespace system;
 
-////BC_PUSH_WARNING(NO_MALLOC_OR_FREE)
 BC_PUSH_WARNING(NO_THROW_IN_NOEXCEPT)
 BC_PUSH_WARNING(NO_UNGUARDED_POINTERS)
 
@@ -93,7 +92,6 @@ typename block::cptr block::deserialize(uint32_t version,
 }
 
 // static
-// WARNING: all shared block components invalidate when the block destructs.
 typename block::cptr block::deserialize(arena& arena, uint32_t version,
     const data_chunk& data, bool witness) NOEXCEPT
 {
@@ -165,7 +163,6 @@ size_t block::size(uint32_t, bool witness) const NOEXCEPT
 
 BC_POP_WARNING()
 BC_POP_WARNING()
-////BC_POP_WARNING()
 
 } // namespace messages
 } // namespace network