How do you remove old wall paper paste??

https://www.wikihow.com/Remove-Wallpaper-Paste#:~:text=%20Soaking%20and%20Wiping%20the%20Walls%20%201,2019.%20Do%20so%20methodically%2C%20section%20by...%20More%20

This link should help:

https://www.bobvila.com/articles/how-to-remove-wallpaper-glue/

Mix 50/50 white vinegar and water or fabric softener & water in a spray bottle. Warm water works best. Saturate and let sit for a few minutes. That should loosen enough to scrape it off.

You can also use a steamer to loosen.

Once you get the serious build up off, wash the walls with warm soapy water (blue Dawn is my preference) and a microfiber cloth.

After it is dry, you are ready to prep & paint.

Here is a list of things that can be used to remove old wall paper paste:

• Mix up your wallpaper paste removal solution. Hot water alone won't do the trick - you'll need a solution that softens the paste, making it easier to remove from the walls. There are a variety of solutions you can use for the job: [6] Hot water and a few squirts of dish soap. This works perfectly well on most wallpaper paste. Fill up a gallon-sized bucket with the solution.
• Hot water and vinegar. This is great for tougher jobs. Mix a gallon of hot water and a gallon of white distilled vinegar.
• Try adding 1 to 2 tablespoons (14.8 to 29.6 ml) of baking soda into the bucket. The baking soda helps to dissolve the wallpaper paste. [7]
• Trisodium phosphate, or TSP. TSP is an industrial-grade cleaner that was once widely used as a cleaner. Is it extremely strong, but not great for the environment, so try using when other, gentler methods have been exhausted. [8]
• For the heaviest jobs, you might want to buy wallpaper paste remover from the store. The commercial removers use chemicals to quickly dissolve the paste. Follow the directions to mix commercial wallpaper paste remover. It is available from most paint or hardware stores, and contains ingredients created specifically to dissolve wallpaper paste

ref:.https://www.wikihow.com/Remove-Wallpaper-Paste

Combine hot water, liquid dish soap, and a tablespoon of baking soda in your bucket. If you find that the glue doesn't come off easily when the solution is applied to the walls, add vinegar to the mix—about 1 cup per gallon of water.

I use a 50/50 mix of vinegar and hot water. Some can be washed off and some may need to be scraped off when it's softened

here is info for you

https://www.bobvila.com/articles/how-to-remove-wallpaper-glue/

Warm water with fabric softener, soak an peel if u can an scrape what u cant

We used hot water and vinegar. Just be careful not to wet the walls too much.