Do you have to clean the washing machine out every time when switching detergent?

kiwi_fruit

I was thinking about trying this product www.charliesoap.com but what surprised me is that it say it's a must to run an empty machine load to get rid of previous residue and then wash clothes couple of times as well for the same reason.
"(For First Time Users) Run an empty load (or perhaps some old rags) with the recommended amount of Charlie's Soap Laundry Liquid or Powder.
This will clear your washing machine of any residue left by previously used detergents and keep them from redepositing on your clothes"

Anybody heard of that before? I'm switching now a lot trying to find suitable and never crossed my mind different detergents can interract badly etc. I'm searching for a all-natural green laundry detergent and tried loads (mostly liquid) but none can shift collar stains, they never come out clean really. No soaking helps etc. Many people swear by this product but I don't want to be only able to use this and have to clean macine everytime after using something else..

SpoonyOh

Soak your shirts in cold water and soda crystals before washing. If you are going to try out this new product, take advantage of the opportunity to boil-wash your dust rags - the hot water (90 degrees I presume) will be a very effective degreaser, leaving your machine residue free.
TBH, I found 'green' detergents a bit questionable, so I use Aldi's Slim Giant concentrated detergent, just use a smaller quantity. A handful of soda crystals in the drawer usually goes a long way.