Home Depot posted a trick that literally everyone needs to try. In your toilet brush holder, pour in some all purpose cleaner. This will help keep the brush clean. And let me tell you, the last thing you want sitting in your bathroom is a dirty toilet brush!!
My husband owned his own A/C business for a long time....he said everything on here is the PROPER way to do this.....do it yourself, will make unit not work so hard and you save $ by not paying the A/C company!