diff --git a/src/policy_all.cpp b/src/policy_all.cpp
index 4bd87e13..31975e5a 100644
--- a/src/policy_all.cpp
+++ b/src/policy_all.cpp
@@ -29,8 +29,6 @@
 
 #include <string>
 
-using std::string;
-
 static
 int
 _create(const Branches::Ptr  &ibranches_,
diff --git a/src/policy_epall.cpp b/src/policy_epall.cpp
index 1ac43c1f..64cc1940 100644
--- a/src/policy_epall.cpp
+++ b/src/policy_epall.cpp
@@ -30,8 +30,6 @@
 
 #include <string>
 
-using std::string;
-
 
 static
 int
diff --git a/src/policy_epff.cpp b/src/policy_epff.cpp
index fb10eeaf..4c4f38df 100644
--- a/src/policy_epff.cpp
+++ b/src/policy_epff.cpp
@@ -31,7 +31,6 @@
 #include <string>
 #include <vector>
 
-using std::string;
 using std::vector;
 
 static
diff --git a/src/policy_eplfs.cpp b/src/policy_eplfs.cpp
index 6ac2ffe2..f3d3e920 100644
--- a/src/policy_eplfs.cpp
+++ b/src/policy_eplfs.cpp
@@ -31,7 +31,6 @@
 #include <string>
 #include <vector>
 
-using std::string;
 using std::vector;
 
 static
diff --git a/src/policy_eplus.cpp b/src/policy_eplus.cpp
index 0b03489f..b29f87ea 100644
--- a/src/policy_eplus.cpp
+++ b/src/policy_eplus.cpp
@@ -30,8 +30,6 @@
 #include <limits>
 #include <string>
 
-using std::string;
-
 static
 int
 _create(const Branches::Ptr  &branches_,
diff --git a/src/policy_erofs.cpp b/src/policy_erofs.cpp
index 89b600b9..0d0e74f8 100644
--- a/src/policy_erofs.cpp
+++ b/src/policy_erofs.cpp
@@ -23,8 +23,6 @@
 
 #include <string>
 
-using std::string;
-
 
 int
 Policy::ERoFS::Action::operator()(const Branches::Ptr  &branches_,
diff --git a/src/policy_lup.cpp b/src/policy_lup.cpp
index 0baabe6e..a93eb362 100644
--- a/src/policy_lup.cpp
+++ b/src/policy_lup.cpp
@@ -33,8 +33,6 @@
 #include <limits>
 #include <string>
 
-using std::string;
-
 static
 int
 _action(const Branches::Ptr  &branches_,
diff --git a/src/policy_lus.cpp b/src/policy_lus.cpp
index b69359df..112dfe69 100644
--- a/src/policy_lus.cpp
+++ b/src/policy_lus.cpp
@@ -32,7 +32,6 @@
 #include <string>
 #include <vector>
 
-using std::string;
 using std::vector;
 
 static
diff --git a/src/policy_mfs.cpp b/src/policy_mfs.cpp
index ad04931c..b6a9f177 100644
--- a/src/policy_mfs.cpp
+++ b/src/policy_mfs.cpp
@@ -28,8 +28,6 @@
 
 #include <string>
 
-using std::string;
-
 
 static
 int
diff --git a/src/policy_newest.cpp b/src/policy_newest.cpp
index e3955f3b..357b606f 100644
--- a/src/policy_newest.cpp
+++ b/src/policy_newest.cpp
@@ -32,8 +32,6 @@
 
 #include <sys/stat.h>
 
-using std::string;
-
 static
 int
 _create(const Branches::Ptr  &branches_,