diff --git a/src/curl.cpp b/src/curl.cpp
index 3419f5f..a4e651b 100644
--- a/src/curl.cpp
+++ b/src/curl.cpp
@@ -4218,6 +4218,7 @@ bool S3fsCurl::UploadMultipartPostComplete()
     if (it == responseHeaders.end()) {
         return false;
     }
+    std::string etag = peeloff(it->second);
 
     // check etag(md5);
     //
@@ -4227,11 +4228,11 @@ bool S3fsCurl::UploadMultipartPostComplete()
     // https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingKMSEncryption.html
     //
     if(S3fsCurl::is_content_md5 && sse_type_t::SSE_C != S3fsCurl::GetSseType() && sse_type_t::SSE_KMS != S3fsCurl::GetSseType()){
-        if(!etag_equals(it->second, partdata.etag)){
+        if(!etag_equals(etag, partdata.etag)){
             return false;
         }
     }
-    partdata.petag->etag = it->second;
+    partdata.petag->etag = etag;
     partdata.uploaded = true;
 
     return true;
@@ -4255,11 +4256,7 @@ bool S3fsCurl::CopyMultipartPostComplete()
 {
     std::string etag;
     partdata.uploaded = simple_parse_xml(bodydata.c_str(), bodydata.size(), "ETag", etag);
-    if(etag.size() >= 2 && *etag.begin() == '"' && *etag.rbegin() == '"'){
-        etag.erase(etag.size() - 1);
-        etag.erase(0, 1);
-    }
-    partdata.petag->etag = etag;
+    partdata.petag->etag = peeloff(etag);
 
     bodydata.clear();
     headdata.clear();
diff --git a/src/curl_util.cpp b/src/curl_util.cpp
index 1816636..3b484d5 100644
--- a/src/curl_util.cpp
+++ b/src/curl_util.cpp
@@ -319,17 +319,9 @@ const char* getCurlDebugHead(curl_infotype type)
 //
 // compare ETag ignoring quotes and case
 //
-bool etag_equals(std::string s1, std::string s2)
+bool etag_equals(const std::string& s1, const std::string& s2)
 {
-    if(s1.length() > 1 && s1[0] == '\"' && *s1.rbegin() == '\"'){
-        s1.erase(s1.size() - 1);
-        s1.erase(0, 1);
-    }
-    if(s2.length() > 1 && s2[0] == '\"' && *s2.rbegin() == '\"'){
-        s2.erase(s2.size() - 1);
-        s2.erase(0, 1);
-    }
-    return 0 == strcasecmp(s1.c_str(), s2.c_str());
+    return 0 == strcasecmp(peeloff(s1).c_str(), peeloff(s2).c_str());
 }
 
 /*
diff --git a/src/curl_util.h b/src/curl_util.h
index 8dc0d7d..596c6d4 100644
--- a/src/curl_util.h
+++ b/src/curl_util.h
@@ -42,7 +42,7 @@ std::string url_to_host(const std::string &url);
 std::string get_bucket_host();
 const char* getCurlDebugHead(curl_infotype type);
 
-bool etag_equals(std::string s1, std::string s2);
+bool etag_equals(const std::string& s1, const std::string& s2);
 
 #endif // S3FS_CURL_UTIL_H_
 
diff --git a/src/string_util.cpp b/src/string_util.cpp
index 0b75a45..8277074 100644
--- a/src/string_util.cpp
+++ b/src/string_util.cpp
@@ -125,6 +125,14 @@ std::string trim(std::string s, const char *t /* = SPACES */)
     return trim_left(trim_right(std::move(s), t), t);
 }
 
+std::string peeloff(std::string s)
+{
+    if(s.size() < 2 || *s.begin() != '"' || *s.rbegin() != '"'){
+        return s;
+    }
+    return s.substr(1, s.size() - 2);
+}
+
 //
 // Three url encode functions
 //
diff --git a/src/string_util.h b/src/string_util.h
index 9132afe..34cdbb1 100644
--- a/src/string_util.h
+++ b/src/string_util.h
@@ -79,6 +79,7 @@ std::string trim_left(std::string s, const char *t = SPACES);
 std::string trim_right(std::string s, const char *t = SPACES);
 std::string trim(std::string s, const char *t = SPACES);
 std::string lower(std::string s);
+std::string peeloff(std::string s);
 
 //
 // Date string
diff --git a/src/test_string_util.cpp b/src/test_string_util.cpp
index 99184df..bdae2e6 100644
--- a/src/test_string_util.cpp
+++ b/src/test_string_util.cpp
@@ -49,6 +49,15 @@ void test_trim()
     ASSERT_EQUALS(std::string("1234"), trim_right("1234  "));
     ASSERT_EQUALS(std::string("  1234"), trim_right("  1234"));
     ASSERT_EQUALS(std::string("1234"), trim_right("1234"));
+
+    ASSERT_EQUALS(std::string("1234"), peeloff("\"1234\""));            // "1234"   -> 1234
+    ASSERT_EQUALS(std::string("\"1234\""), peeloff("\"\"1234\"\""));    // ""1234"" -> "1234"
+    ASSERT_EQUALS(std::string("\"1234"), peeloff("\"\"1234\""));        // ""1234"  ->  "1234
+    ASSERT_EQUALS(std::string("1234\""), peeloff("\"1234\"\""));        // "1234""  -> 1234"
+    ASSERT_EQUALS(std::string("\"1234"), peeloff("\"1234"));            // "1234    -> "1234
+    ASSERT_EQUALS(std::string("1234\""), peeloff("1234\""));            // 1234"    -> 1234"
+    ASSERT_EQUALS(std::string(" \"1234\""), peeloff(" \"1234\""));      // _"1234"  -> _"1234"
+    ASSERT_EQUALS(std::string("\"1234\" "), peeloff("\"1234\" "));      // "1234"_  -> "1234"_
 }
 
 void test_base64()