Umbraco Forms - Extension methods to remove specific providers, e.g. removing a FieldType, such as Recaptcha

ProviderCollectionExtensions.cs

using System;
using System.Collections.Generic;
using System.Reflection;
using Umbraco.Forms.Core.Common;

namespace Our.Umbraco.Web.Extensions
{
    public static class ProviderCollectionExtensions
    {
        public static void RemoveProvider<T>(this ProviderCollection<T> collection, params string[] providerIds)
            where T : ProviderBase
        {
            var guids = new List<Guid>();
            foreach (var providerId in providerIds)
            {
                if (Guid.TryParse(providerId, out Guid id))
                    guids.Add(id);
            }

            RemoveProvider(collection, guids.ToArray());
        }

        public static void RemoveProvider<T>(this ProviderCollection<T> collection, params Guid[] providerIds)
            where T : ProviderBase
        {
            var type = typeof(ProviderCollection<T>);

            var field = type.GetField("m_providers", BindingFlags.GetField | BindingFlags.NonPublic | BindingFlags.Instance);
            if (field == null)
                return;

            var providers = (Dictionary<Guid, T>)field.GetValue(collection);
            if (providers == null)
                return;

            foreach (var providerId in providerIds)
            {
                if (providers.ContainsKey(providerId))
                {
                    providers.Remove(providerId);
                }
            }
        }
    }
}

Related ticket on the Umbraco issue tracker: http://issues.umbraco.org/issue/CON-1196

Can you provide an example of how to use this to remove the old reCaptcha from the list of available Umbraco Forms field types? I can't figure out how to get it to work.
Thanks

I'm doing RemoveProvider(FieldTypeProviderCollection.Instance, new Guid("fb37bc60-d41e-11de-aeae-37c155d89593")); in the OnApplicationStarted of a IApplicationEventHandler, where that is the guid of the password field that I found debugging. Works nicely, thanks lee!