ConsoleTools.cs

using System;
using System.Reflection;
using UnityEditor;

namespace Zapdot
{
    public static class ConsoleTools
    {
        public static void ClearLog()
        {
            Assembly assembly = Assembly.GetAssembly(typeof(SceneView));

            Type type = assembly.GetType("UnityEditorInternal.LogEntries");
            MethodInfo method = type.GetMethod("Clear");
            method.Invoke(new object(), null);
        }
    }
}