This subject maybe OT but I am going to take a chance anyway.

Just removed decals on my 97’ Nissan truck. I used a rubber eraser wheel for drill and it did a very good job. One side of the bed, however, was repainted years back. The existing decals were taped and sprayed over. This created a paint buildup which made the decals outline visible when the decals were removed.

My question is, can these outlines be removed with a rubbing compound and a buffer action?
Even though this is a good little truck with 84K original miles and excellent paint, It is not worth it for me to have this side repainted. If I have to live with these outlines, I guess I will.

Tough question to answer. When the truck was repainted was single stage paint used or was it clear coated? When you tried removing the decals and went through the clear coat and the base coat the shadow will be permanent unless the area is repainted. Same thing with the single stage. You can try using a fine rubbing compound,a spray on decal remover or wet sanding with a 4000 grit sand paper and go over the area with a fine compound.

You might want to get an estimate to have that side repainted using a single stage paint? More affordable. You could sand the area yourself using a scuff pad or a fine sand paper. Get an estimate both ways? Worked at a bus garage for years and I firmly believe you can only see one side of a vehicle at a time that’s why when I was in a hurry I only washed the passenger side. Same would apply painting your vehicle. The paint job may not be perfect but will make the vehicle more presentable.