diff --git a/bijection-core/src/main/scala/com/twitter/bijection/EnglishInt.scala b/bijection-core/src/main/scala/com/twitter/bijection/EnglishInt.scala
index f57b45a4d..c9a32086c 100644
--- a/bijection-core/src/main/scala/com/twitter/bijection/EnglishInt.scala
+++ b/bijection-core/src/main/scala/com/twitter/bijection/EnglishInt.scala
@@ -13,7 +13,7 @@
 
 package com.twitter.bijection
 
-case class EnglishInt(get: String)
+case class EnglishInt(get: String) extends AnyVal
 
 object EnglishInt {
   implicit val bijectionToInt: Bijection[Int, EnglishInt] = new AbstractBijection[Int, EnglishInt] {
diff --git a/bijection-core/src/main/scala/com/twitter/bijection/NumberSystems.scala b/bijection-core/src/main/scala/com/twitter/bijection/NumberSystems.scala
index 33672a313..d231380c7 100644
--- a/bijection-core/src/main/scala/com/twitter/bijection/NumberSystems.scala
+++ b/bijection-core/src/main/scala/com/twitter/bijection/NumberSystems.scala
@@ -6,9 +6,9 @@
 package com.twitter.bijection
 
 object NumberSystems {
-  case class BinaryString(get: String)
-  case class HexString(get: String)
-  case class OctalString(get: String)
+  case class BinaryString(get: String) extends AnyVal
+  case class HexString(get: String) extends AnyVal
+  case class OctalString(get: String) extends AnyVal
   case class ArbitBaseString(get: String, base: Int)
 
   implicit val binary: Bijection[Int, BinaryString] = new AbstractBijection[Int, BinaryString] {
diff --git a/bijection-core/src/main/scala/com/twitter/bijection/StringInjections.scala b/bijection-core/src/main/scala/com/twitter/bijection/StringInjections.scala
index 3f340c1ea..de1db2085 100644
--- a/bijection-core/src/main/scala/com/twitter/bijection/StringInjections.scala
+++ b/bijection-core/src/main/scala/com/twitter/bijection/StringInjections.scala
@@ -26,6 +26,8 @@ import com.twitter.bijection.Inversion.attempt
 import scala.util.Try
 
 trait StringInjections extends NumericInjections {
+  import StringCodec.URLEncodedString
+
   implicit val utf8: Injection[String, Array[Byte]] = withEncoding("UTF-8")
 
   def withEncoding(encoding: String): Injection[String, Array[Byte]] =
@@ -48,8 +50,6 @@ trait StringInjections extends NumericInjections {
       override def invert(s: String) = attempt(s)(UUID.fromString(_))
     }
 
-  case class URLEncodedString(encodedString: String)
-
   implicit val string2UrlEncodedString: Injection[String, URLEncodedString] = new AbstractInjection[String, URLEncodedString] {
     override def apply(a: String): URLEncodedString = URLEncodedString(URLEncoder.encode(a, "UTF-8"))
 
@@ -57,4 +57,6 @@ trait StringInjections extends NumericInjections {
   }
 }
 
-object StringCodec extends StringInjections
+object StringCodec extends StringInjections {
+  case class URLEncodedString(encodedString: String) extends AnyVal
+}
diff --git a/bijection-guava/src/main/scala/com/twitter/bijection/guava/GuavaBinaryBijections.scala b/bijection-guava/src/main/scala/com/twitter/bijection/guava/GuavaBinaryBijections.scala
index 3b6c4da0d..fb7a368bf 100644
--- a/bijection-guava/src/main/scala/com/twitter/bijection/guava/GuavaBinaryBijections.scala
+++ b/bijection-guava/src/main/scala/com/twitter/bijection/guava/GuavaBinaryBijections.scala
@@ -23,19 +23,19 @@ import com.google.common.io.BaseEncoding
  */
 object GuavaBinaryBijections {
 
-  trait BaseEncoding {
-    val str: String
+  trait BaseEncoding extends Any {
+    def str: String
   }
 
-  case class Base16String(str: String) extends BaseEncoding
+  case class Base16String(str: String) extends AnyVal with BaseEncoding
 
-  case class Base32String(str: String) extends BaseEncoding
+  case class Base32String(str: String) extends AnyVal with BaseEncoding
 
-  case class Base32HEXString(str: String) extends BaseEncoding
+  case class Base32HEXString(str: String) extends AnyVal with BaseEncoding
 
-  case class Base64String(str: String) extends BaseEncoding
+  case class Base64String(str: String) extends AnyVal with BaseEncoding
 
-  case class Base64URLString(str: String) extends BaseEncoding
+  case class Base64URLString(str: String) extends AnyVal with BaseEncoding
 
   implicit def unwrap(encodedString: BaseEncoding): String = Option(encodedString) match {
     case Some(x) => x.str
diff --git a/bijection-json/src/main/scala/com/twitter/bijection/json/UnparsedJson.scala b/bijection-json/src/main/scala/com/twitter/bijection/json/UnparsedJson.scala
index 84b836ad5..1969855c5 100644
--- a/bijection-json/src/main/scala/com/twitter/bijection/json/UnparsedJson.scala
+++ b/bijection-json/src/main/scala/com/twitter/bijection/json/UnparsedJson.scala
@@ -24,9 +24,8 @@ import org.codehaus.jackson.JsonNode
 
 /**
  * Value class representing unparsed Json text
- * TODO in scala 2.10 this should be a value class
  */
-case class UnparsedJson(str: String)
+case class UnparsedJson(str: String) extends AnyVal
 
 object UnparsedJson {