This sort of depends on the type of paste your trying to remove. When we need an especially strong adhesive, we mix clay based adhesive with border adhesive. The result is a paste that is much stronger than either by themselves. The unfortunate part is that down the road this adhesive cures as hard as cement and will not desolve no matter how much water is used.
Try this. Wet an area of the wall and stick a paper towel to it. Then wet the paper towel (a trigger spray bottle works well for this). Keep the towel wet for about 20 minutes. Then try to scrape the paste off with a 6 inch tapeing knife by pulling the knife over the wet paste. If this works, then get your self a garden type compression sprayer, fill it with water and some TSP and wet an area as large as you can keep wet and keep it wet for the same 20 minutes. Then, while your scraping that area, wet the next so it can soak while you clean the first. Immediatly follow the scraping with a washing with clear water( I use a large clamshell sponge for this), changing the wash water often.
When scraping the paste, it is important that you pull the scraper, don't push it. Wet walls damage easily. Pushing the scraper will dig into the wall surface.
If this expirement doesn't work, then your best bet is to skim coat the walls with several coats of joint compound and start over.
There was a post on this subject a while back where one person suggested using Peel-Away 1. This is a Sodium Hydroxide paint stripper that is fairly mild compared to the typical Methylene Chloride stripper. I can see where this would be worth expirementing with if your walls are plaster, but drywall would never hold up to this chemical.