Seafoam spray

right I used 80% of can in my MPS 3 Throttle feels more responsive now I'm I'm just wondering if it will be safe to use on my partners 05 Daihatsu boon 1.0 3cylinder

There seems to be lots of positive stuff around about its use. Depending on how you used it, I cant see any harm from 1/4 can.
I have seen videos of people taking the brake booster pipe off and squirting it into there while the engine is running at a fast idle. It seems to get rid of a lot of crap from inside the engine. It is possible that the same effect could have been achieved by using a weed sprayer to squirt water in there once the engine was good and hot.
I have seen a Wheeler Dealers episode where they used a proprietary product called terraclean which got rid of carbon etc and reduced emissions to a level that would pass the British MOT standards.

My comments about water spray are from experience where my Nissan 720 ute had a very slow coolant leak into the cylinder. When it finally let go and became a problem and the head was taken off, the combustion chamber and top of the piston in the faulty cylinder looked like it was brand new. The small amount of water had kept it totally clean and new looking. Weird but true!

yup mate had an outboard with a bad jacket. piston and head were spotless

De coke , or using water was a old trick to try to remove carbon build up .
Also water vabour has been around for a long time, used to be thought you could get more miles per gallon ,
I have a small unit here , made for a single cylinder motor.
Only thing was you needed to retard the spark as it caused a bit of pinging / knock in the motor if the water jet allowed too much water in.

Yes, water injection into a hot engine aided fuel atomisation in the pre EFI days.