diff --git a/Creek.FileRepository/Helpers/StringHelper.cs b/Creek.FileRepository/Helpers/StringHelper.cs
index 82e235b..fa19330 100644
--- a/Creek.FileRepository/Helpers/StringHelper.cs
+++ b/Creek.FileRepository/Helpers/StringHelper.cs
@@ -4,8 +4,16 @@ using System.Text;
 
 namespace Creek.FileRepository.Helpers
 {
+    /// <summary>
+    /// A helper class for string methods.
+    /// </summary>
     internal class StringHelper
     {
+        /// <summary>
+        /// Checks if a filename contains invalid characters.
+        /// </summary>
+        /// <param name="filename">The filename to be checked.</param>
+        /// <returns>Returns true if the filename contains invalid characters.</returns>
         public static bool IsInvalidFileName(string filename)
         {
             char[] invalidCharacters = new char[] { '<', '>', ':', '\'', '/', '\\', '|', '?', '*' };
@@ -13,10 +21,15 @@ namespace Creek.FileRepository.Helpers
             return Array.Exists(invalidCharacters, character => filename.Contains(character.ToString()));
         }
 
+        /// <summary>
+        /// Sanitises a filename containing invalid characters.
+        /// </summary>
+        /// <param name="originalFileName">The filename to sanitise.</param>
+        /// <returns>Returns the sanitised filename.</returns>
         internal static string MakeValidFileName(string originalFileName)
         {
             char[] invalids = System.IO.Path.GetInvalidFileNameChars();
-            string validFileName = String.Join("_", originalFileName.Split(invalids, StringSplitOptions.RemoveEmptyEntries)).TrimEnd('.');
+            string validFileName = string.Join("_", originalFileName.Split(invalids, StringSplitOptions.RemoveEmptyEntries)).TrimEnd('.');
 
             // Additionally remove Windows characters explicitly, in case we're running on Linux (e.g. in Docker) but need to access the files in Windows
             string[] charsToRemove = new string[] { "<", ">", ":", "\"", "/", "\\", "|", "?", "*" };
@@ -26,6 +39,12 @@ namespace Creek.FileRepository.Helpers
             return validFileName;
         }
 
+        /// <summary>
+        /// Removes any characters in an array of strings from a string.
+        /// </summary>
+        /// <param name="charsToRemove">The string array of characters to remove.</param>
+        /// <param name="str">The string to modify.</param>
+        /// <returns>Returns the modified string.</returns>
         internal static string RemoveCharsFromString(string[] charsToRemove, string str)
         {
             foreach (string c in charsToRemove)