diff --git a/toonz/sources/common/tsystem/tbigmemorymanager.cpp b/toonz/sources/common/tsystem/tbigmemorymanager.cpp
index 3feef28..a8d077b 100644
--- a/toonz/sources/common/tsystem/tbigmemorymanager.cpp
+++ b/toonz/sources/common/tsystem/tbigmemorymanager.cpp
@@ -424,17 +424,17 @@ TRaster *TBigMemoryManager::findRaster(TRaster *ras)
 void TBigMemoryManager::printMap()
 {
 	std::map<UCHAR *, Chunkinfo>::iterator it = m_chunks.begin();
-	TSystem::outputDebug("BIGMEMORY chunks totali: " + toString((int)m_chunks.size()) + "\n");
+	TSystem::outputDebug("BIGMEMORY chunks totali: " + std::to_string((int)m_chunks.size()) + "\n");
 
 	int count = 0;
 
 	while (it != m_chunks.end()) {
 		TSystem::outputDebug("chunk #" +
-							 toString((int)count++) +
+							 std::to_string((int)count++) +
 							 "dimensione(kb):" +
-							 toString((int)(it->second.m_size >> 10)) +
+							 std::to_string((int)(it->second.m_size >> 10)) +
 							 "num raster:" +
-							 toString((int)(it->second.m_rasters.size())) +
+							 std::to_string((int)(it->second.m_rasters.size())) +
 							 "\n");
 
 		it++;
diff --git a/toonz/sources/common/tvectorimage/tcomputeregions.cpp b/toonz/sources/common/tvectorimage/tcomputeregions.cpp
index 4befbe2..d569352 100644
--- a/toonz/sources/common/tvectorimage/tcomputeregions.cpp
+++ b/toonz/sources/common/tvectorimage/tcomputeregions.cpp
@@ -2742,19 +2742,6 @@ void printStrokes1(vector<VIStroke *> &v, int size)
 }
 
 //-----------------------------------------------------------------------------
-#ifdef _DEBUG
-static void printTime(TStopWatch &sw, string name)
-{
-	ostrstream ss;
-	ss << name << " : ";
-	sw.print(ss);
-	ss << '\n' << '\0';
-	string s = ss.str();
-	ss.freeze(false);
-	//TSystem::outputDebug(s);
-}
-#endif
-//-----------------------------------------------------------------------------
 void printStrokes1(vector<VIStroke *> &v, int size);
 
 //void testHistory();
diff --git a/toonz/sources/toonzlib/stage.cpp b/toonz/sources/toonzlib/stage.cpp
index cd8425f..4e0c2e7 100644
--- a/toonz/sources/toonzlib/stage.cpp
+++ b/toonz/sources/toonzlib/stage.cpp
@@ -715,28 +715,6 @@ void StageBuilder::visit(PlayerSet &players, Visitor &visitor, bool isPlaying)
 
 //=============================================================================
 
-#ifdef _DEBUG
-// debug
-class DummyVisitor : public Visitor
-{
-	std::ostrstream m_ss;
-
-public:
-	void onImage(const Stage::Player &data) { m_ss << "img "; }
-	void beginMask() { m_ss << "beginMask "; }
-	void endMask() { m_ss << "endMask "; }
-	void enableMask() { m_ss << "enableMask "; }
-	void disableMask() { m_ss << "disableMask "; }
-	std::string getLog()
-	{
-		m_ss << '\0';
-		std::string log = m_ss.str();
-		m_ss.freeze(0);
-		return log;
-	}
-};
-#endif
-
 //=============================================================================
 /*! Declare a \b StageBuilder object and recall \b StageBuilder::addFrame() and
 		\b StageBuilder::visit().
diff --git a/toonz/sources/toonzlib/texturemanager.cpp b/toonz/sources/toonzlib/texturemanager.cpp
index fc7a18b..29186bf 100644
--- a/toonz/sources/toonzlib/texturemanager.cpp
+++ b/toonz/sources/toonzlib/texturemanager.cpp
@@ -4,6 +4,8 @@
 #include "tsystem.h"
 #include "toonz/preferences.h"
 
+#include <sstream>
+
 //==============================================================================
 //
 //TextureManager
@@ -55,10 +57,9 @@ TDimensionI TextureManager::getMaxSize(bool isRGBM)
 			glGetTexLevelParameteriv(GL_PROXY_TEXTURE_2D, 0, GL_TEXTURE_COMPONENTS, &cmpt);
 
 			if (outX && outY) {
-				std::ostrstream os;
+				std::stringstream os;
 				os << "texture size = " << outX << "x" << outY << " fmt " << intFmt << " cmpt# " << cmpt << " " << rSize << "," << gSize << "," << bSize << "," << aSize << '\n' << '\0';
 				TSystem::outputDebug(os.str());
-				os.freeze(false);
 			}
 #endif
 		} while ((outX == texLx) && (outY == texLy));