**Yes—faint, firmly attached residue can remain if you seal it before applying the skim coat.** Remove any raised glue deposits and loose material first. Zinsser’s [Gardz technical sheet](https://www.rustoleum.com/~/media/DigitalEncyclopedia/Documents/RustoleumUSA/TDS/English/CBG/Zinsser/GDZ-01_GARDZ_High_Performance_Sealer_TDS.ashx) specifically allows residual wallpaper adhesive after thicker deposits have been removed.

A faint stain alone doesn’t tell you whether glue remains. Dampen a small spot: if it becomes slippery or gummy, keep cleaning that area gently. Avoid scraping so aggressively that you tear the drywall paper.

For your next steps:

1. Wipe the wall with clean water to remove loosened glue and cleaning solution, then let it dry thoroughly.
2. Apply a sealer specifically rated for wallpaper adhesive residue, such as Gardz, across the wall.
3. Let the sealer dry according to its label, then skim coat.
4. After the mud dries, sand and prime before painting.

Sealing matters because moisture can reactivate leftover paste and cause cracking or peeling. Gardz is also rated for joint compound applied over it. [Manufacturer guidance](https://www.rustoleum.com/~/media/DigitalEncyclopedia/Documents/RustoleumUSA/TDS/English/CBG/Zinsser/GDZ-01_GARDZ_High_Performance_Sealer_TDS.ashx).