How do I know if I need to score the wallpaper?

Try peeling it off first. If it peels off in small pieces, then scoring it will allow the remover to penetrate to loosen the paper.

Will PIRANHA Scoring Tool work on several layers of old wallpaper?

Yes.

How do I know when the wallpaper is ready to be removed?

After applying the remover, allow 10-15 minutes for the remover to loosen paper and start dissolving the paste behind it. Begin removing the old wallpaper when it turns darker or starts to bubble.

There is adhesive still on the wall after I have removed the wallpaper. What do I do?

Just re-apply PIRANHA, wait 10-15 minutes, then use PIRANHA Removal Sponge with Scrubber to take off residual adhesive. Rinse with clean water.