diff --git a/src/Microsoft.ML.Data/Dirty/PredictionUtils.cs b/src/Microsoft.ML.Data/Dirty/PredictionUtils.cs
index 653a05fbb7..6ade2b5e1d 100644
--- a/src/Microsoft.ML.Data/Dirty/PredictionUtils.cs
+++ b/src/Microsoft.ML.Data/Dirty/PredictionUtils.cs
@@ -16,7 +16,8 @@ namespace Microsoft.ML.Internal.Internallearn
     /// <summary>
     /// Various utilities
     /// </summary>
-    public static class PredictionUtil
+    [BestFriend]
+    internal static class PredictionUtil
     {
         /// <summary>
         /// generic method for parsing arguments using CommandLine. If there's a problem, it throws an InvalidOperationException, with a message giving usage.
@@ -152,16 +153,4 @@ public static char SepCharFromString(string s)
             }
         }
     }
-
-    /// <summary>
-    /// A generic reverse Comparer (for use in Array.Sort)
-    /// </summary>
-    public sealed class ReverseComparer<T> : IComparer<T>
-        where T : IComparable<T>
-    {
-        public int Compare(T x, T y)
-        {
-            return -x.CompareTo(y);
-        }
-    }
 }
\ No newline at end of file
diff --git a/src/Microsoft.ML.Data/Dirty/PredictorInterfaces.cs b/src/Microsoft.ML.Data/Dirty/PredictorInterfaces.cs
index e4d83f8adc..1b956ed2d0 100644
--- a/src/Microsoft.ML.Data/Dirty/PredictorInterfaces.cs
+++ b/src/Microsoft.ML.Data/Dirty/PredictorInterfaces.cs
@@ -11,12 +11,6 @@
 
 namespace Microsoft.ML.Internal.Internallearn
 {
-
-    /// <summary>
-    /// Signature for loading from a file name.
-    /// </summary>
-    public delegate void SignaturePredictorFromFile(string fileName);
-
     /// <summary>
     /// A generic interface for models that can average parameters from multiple instance of self
     /// </summary>
@@ -146,7 +140,8 @@ internal interface ICanSaveInSourceCode
     /// <summary>
     /// Signature for trainers that produce predictors that in turn can be use to score features.
     /// </summary>
-    public delegate void SignatureFeatureScorerTrainer();
+    [BestFriend]
+    internal delegate void SignatureFeatureScorerTrainer();
 
     /// <summary>
     /// Interface implemented by components that can assign weights to features.
diff --git a/src/Microsoft.ML.Data/Training/EarlyStoppingCriteria.cs b/src/Microsoft.ML.Data/Training/EarlyStoppingCriteria.cs
index 6a53a5d2ce..0481f51280 100644
--- a/src/Microsoft.ML.Data/Training/EarlyStoppingCriteria.cs
+++ b/src/Microsoft.ML.Data/Training/EarlyStoppingCriteria.cs
@@ -23,7 +23,7 @@
 
 namespace Microsoft.ML.Internal.Internallearn
 {
-    public delegate void SignatureEarlyStoppingCriterion(bool lowerIsBetter);
+    internal delegate void SignatureEarlyStoppingCriterion(bool lowerIsBetter);
 
     // These criteria will be used in FastTree and NeuralNets.
     public interface IEarlyStoppingCriterion
diff --git a/src/Microsoft.ML.Data/Utilities/SlotDropper.cs b/src/Microsoft.ML.Data/Utilities/SlotDropper.cs
index c01adb761d..b720ebf703 100644
--- a/src/Microsoft.ML.Data/Utilities/SlotDropper.cs
+++ b/src/Microsoft.ML.Data/Utilities/SlotDropper.cs
@@ -12,7 +12,8 @@ namespace Microsoft.ML.Internal.Internallearn
     /// <summary>
     /// Drops slots from a fixed or variable sized column based on slot ranges.
     /// </summary>
-    public sealed class SlotDropper
+    [BestFriend]
+    internal sealed class SlotDropper
     {
         private readonly int[] _lengthReduction;
 
diff --git a/src/Microsoft.ML.Data/Utilities/TypeUtils.cs b/src/Microsoft.ML.Data/Utilities/TypeUtils.cs
deleted file mode 100644
index eb91b97100..0000000000
--- a/src/Microsoft.ML.Data/Utilities/TypeUtils.cs
+++ /dev/null
@@ -1,96 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-using System;
-using System.Linq;
-using System.Text;
-using System.Text.RegularExpressions;
-using Microsoft.ML.Internal.Utilities;
-
-namespace Microsoft.ML.Internal.Internallearn
-{
-    public static class TypeUtils
-    {
-        /// <summary>
-        /// Returns a pretty representation of the type.
-        /// </summary>
-        public static string PrettyName(Type type)
-        {
-            Contracts.AssertValue(type, "type");
-            StringBuilder sb = new StringBuilder();
-            BuildPrettyName(type, sb);
-            return sb.ToString();
-        }
-
-        private static void BuildPrettyName(Type type, StringBuilder sb)
-        {
-            // Arrays
-            if (type.IsArray)
-            {
-                // Store the original and walk to get the non-array element type.
-                Type origType = type;
-                while (type.IsArray)
-                    type = type.GetElementType();
-                BuildPrettyName(type, sb);
-                // Rewalk to get the [] items in indexing order.
-                type = origType;
-                while (type.IsArray)
-                {
-                    sb.Append('[');
-                    for (int i = 1; i < type.GetArrayRank(); ++i)
-                        sb.Append(',');
-                    sb.Append(']');
-                    type = type.GetElementType();
-                }
-                return;
-            }
-            // Output the names of generic parameters.
-            if (type.IsGenericParameter)
-            {
-                Contracts.Assert(type.FullName == null);
-                sb.Append(type.Name);
-                return;
-            }
-            // Get excluding the namespace and any possible following type-array.
-            string name = type.FullName ?? type.Name;
-            Match m = Regex.Match(type.FullName, @"^(?:\w+\.)*([^\[]+)");
-            Contracts.Assert(m.Success);
-            Contracts.Assert(m.Groups.Count == 2);
-            string[] subNames = m.Groups[1].Value.Split('+');
-            // Get the generic type arguments, if there are any.
-            Type[] genTypes = type.IsGenericType ? type.GetGenericArguments() : null;
-            int iGenTypes = 0;
-
-            for (int i = 0; i < subNames.Length; ++i)
-            {
-                if (i > 0)
-                    sb.Append('.');
-                string subName = subNames[i];
-                if (!subName.Contains('`'))
-                {
-                    sb.Append(subName);
-                    continue;
-                }
-                string[] subparts = subName.Split('`');
-                Contracts.Assert(subparts.Length == 2);
-                Contracts.Assert(type.IsGenericType);
-                sb.Append(subparts[0]);
-                sb.Append('<');
-                int numGenerics = int.Parse(subparts[1]);
-                Contracts.Assert(iGenTypes + numGenerics <= Utils.Size(genTypes));
-                while (numGenerics-- > 0)
-                {
-                    Type parameter = genTypes[iGenTypes++];
-                    // Leave generic parameters as blank.
-                    if (!parameter.IsGenericParameter)
-                        BuildPrettyName(parameter, sb);
-                    if (numGenerics > 0)
-                        sb.Append(',');
-                }
-                sb.Append('>');
-            }
-            Contracts.Assert(iGenTypes == Utils.Size(genTypes));
-        }
-    }
-}