I'm in the middle of replacing some old carpet in my house with engineered hardwood boards. They're tongue and groove and I'll be nailing the boards down in the end. To that end, I had to remove the particle board layer covering my plywood subfloor.
After starting on the particle board removal, I found them to be glued down, in addition to the visible nails. I've gotten all the boards up, but now I'm left with patches where the glue lines were down.
On one side of the room the subfloor ply is hard enough that I was able to chisel up the lines and it's all relatively flat now. On the other, however, the boards are much softer and as such tend to splinter and tear up when trying to get the glue piles up.
Is there any technique to do this effectively? I've also tried sanding the areas down, but it's hard to keep it from hitting the subfloor and is very slow work.