Rain washes blood and dirt away. Including the character's body, clothing, equipped bags, equipped and attached weapons, the vehicle your character is in and vehicle attached to it or last used vehicle and vehicle attached to it.

• Body, clothing, bags, weapons
• When it's raining and your character is outside (and not in a car, of course) the mentioned things will slowly be cleaned. The process begins as soon as a body part* or item becomes wet: some of its blood is turned into dirt, then the dirt is washed away.
• Not everything is cleaned at the same time! Notice how wetness is increased: top layer of clothing / uncovered body parts -> inner layer of clothing -> covered body parts. It's a vanilla mechanic.
• How fast an item or body will be cleaned depends on rain intensity and the item's or body's wetness.
• Not all dirt will be washed off clothes! Depending on the water resistance of the clothing, up to 20% of dirt will remain.
• Not all dirt will be washed off your character! Up to 10% of dirt will remain.
• *The character's body does not get wet in the God mode!
• **Any makeup will be removed as soon as the character's head is 100% wet.

• The vehicle your character is in and the vehicle attached to it will be cleaned.
• The last used vehicle and the vehicle attached to it will be cleaned after your character leaves it too. This works as long as your character is within approximately 100 squares of these vehicles. After reloading the save you need to enter/exit again for this to work.

If you want to configure the mod, you need to install and enable the Mod Options mod.
Go to Options -> Mods -> Rain Wash.

Game version: IWBUMS Build 41.56+

This mod is compatible with:
- any mods that add clothing, bags and weapons;
- any mods that add/change character traits;
- any mods that add vehicles.

Steam Remote Play - never played together, did not test, do not support. Sorry :(
However, it might work because the mod is written with that in mind.
I'll be very grateful if you try and let me know. If you and your friend hover over bloody/dirty clothing in the inventory when it's raining (your characters should be outside) and blood/dirt is washed off for both, this means that mod works as it should. Only one thing will be a bit off: if you and your friends are in the same vehicle, it will be cleaned faster than it should.

Does this mod work with existing saves?
Yes. You can enable or disable it at any time.

• Does this mod wash away blood from all vehicles?
  
• Does this mod wash away blood/dirt from clothing/weapons on the ground?
  
• Does this mod wash blood off the ground/walls?
  
• Does this mod remove ashes from the ground?

No. No. No. And NO. And never will. Some of these features are possible, but will greatly affect performance.