An initialization module that checks both page- and blocktypes for properties that are no longer defined in code and deletes them. Link to blog post: http://world.episerver.com/blogs/Per-Nergard/Dates/2016/4/missing-properties-initializationmodule/

Missingprooperties init module

using System;
using EPiServer.Framework;
using EPiServer.Framework.Initialization;
using System.Web.Configuration;
using EPiServer.DataAbstraction;
using EPiServer.ServiceLocation;
using System.Collections.Generic;

namespace AlloyDemoKit.Business.Initialization
{
    [InitializableModule]
    [ModuleDependency(typeof(EPiServer.Web.InitializationModule))]
    public class MissingProperties : IInitializableModule
    {

        public void Initialize(InitializationEngine context)
        {
            if (GoAHead)
            {
                DeleteMissingProperties(GetMissingProperties());
            }
        }

        public void Uninitialize(InitializationEngine context)
        {
            //We don't attach any events so we don't do anything
        }

        /// <summary>
        /// Implement whatever activation mechanism that fits your needs. 
        /// </summary>
        private bool GoAHead
        { 
            get
            {
                return Convert.ToBoolean(WebConfigurationManager.AppSettings.Get("AutoDeleteMissingProperties"));
            }
        }

        /// <summary>
        /// Get all properties that are not defined in code anymore.
        /// </summary>
        /// <returns></returns>
        private List<PropertyDefinition> GetMissingProperties()
        {
            IContentTypeRepository contentTypeRepository = ServiceLocator.Current.GetInstance<IContentTypeRepository>();

            List<PropertyDefinition> propertyDefinitions = new List<PropertyDefinition>();

            foreach (var type in contentTypeRepository.List())
            {
                foreach (var property in type.PropertyDefinitions)
                {
                    if (IsMissingModelProperty(property)) propertyDefinitions.Add(property);
                }
            }

            return propertyDefinitions;
        }

        /// <summary>
        /// Is propertydefinition not defind in code?
        /// </summary>
        /// <param name="propertyDefinition"></param>
        /// <returns></returns>
        private bool IsMissingModelProperty(PropertyDefinition propertyDefinition)
        {
            ContentTypeModelRepository typeModelRepository = ServiceLocator.Current.GetInstance<ContentTypeModelRepository>();

            return (((propertyDefinition != null) && propertyDefinition.ExistsOnModel) && (typeModelRepository.GetPropertyModel(propertyDefinition.ContentTypeID, propertyDefinition) == null));
        }

        /// <summary>
        /// Delete property definitions
        /// </summary>
        /// <param name="propertiesToDelete"></param>
        private void DeleteMissingProperties(List<PropertyDefinition> propertiesToDelete)
        {
            IPropertyDefinitionRepository propertyDefinitionRepository = ServiceLocator.Current.GetInstance<IPropertyDefinitionRepository>();

            foreach (var propertyDefinition in propertiesToDelete)
            {
                propertyDefinitionRepository.Delete(propertyDefinition);
            }
        }
    }
}