1.Use warm water: Prepare a basin of warm water and soak the old couplets in warm water for a while to allow the glue to soften. Then, use a damp cloth or sponge dipped in warm water and gently rub the glue part of the couplet until the glue gradually dissolves or softens. Finally, gently wipe dry with a clean cloth.
2.Use vinegar or lemon juice: Both vinegar and lemon juice have the effect of dissolving glue. You can apply an appropriate amount of vinegar or lemon juice to the glue part of the old couplet, let it sit for a few minutes, and then wipe it with a damp cloth, the glue may gradually dissolve. Finally, wipe dry with a clean cloth.
3.Use an eraser: Fix the old couplet on a flat surface, then gently wipe the glue part with the eraser, back and forth, the glue may gradually be absorbed by the eraser. This method requires patience and meticulous wiping so as not to damage the surface of the couplet.
4.Use wind oil essence or soap: Apply an appropriate amount of wind oil essence or soap to the old couplet glue and let it sit for a while. Next, wipe with a damp cloth dipped in warm water, the glue may gradually soften. Finally, wipe dry with a clean cloth.
It should be noted that the above methods should be used with caution to avoid damage to the couplet. Before using any solvents or chemicals, test them in an inconspicuous place to make sure you don't damage the color or material of the couplet.
Also, if the glue on the couplet is stubborn or heavy, you can try multiple treatments or use a professional glue remover.