Saline 0.9% is widely used to irrigate fresh wounds, flushing out debris that can cause an infection and delay healing. It is also used for eye irrigation.
Saline or slat water doesn't clean as such, but will get rid of debris and is used as a first line treatment, however you need a good flow of fluid to thoroughly wash the area. Many 1st Aid kits contain the 20ml pods of saline, which aew expensive and do not contain enough volume.
I have found these 500ml bottle, which are really economical to buy, (much cheaper than the saline pods), and isn't too big to have in the car on standby.
The bottles contain sterile saline, 0.9% which is the correct strength to use.
Home made saline can be fraught with problems as is either too strong or too weak, both of which will dleay healing.
The saline can also be bought in out 1st Aid packs along with other essentials. They can be found here.