If your talking about applying a product like Formica you would be so much better off just removing what you have and make all new ones.
Extremely hard to line it up when trying to place it, once the material touchs it's near impossible to more it to realign it.
Very hard to trim the edges where it comes close to the walls.
Why take the chance of it not sticking.
The laminite needs to make 100% contact with the surface below.
You can apply new contact cement (use the flammable kind) over the old.
Acetone will dissolve the cement. You can squirt acetone into the gap between the laminate and substrate, continuing to squirt acetone and lifting up laminate, to remove the laminate if you happen to make mistake aligning them.
Having said it, work will be easier, dust control better and finish more exact by removing the substrate, if it was installed as a removeable.
Don't try to sand the old glue. Feel around and scrape/dissolve any speck or spot that feels different from the rest.
A forum community dedicated to Do it yourself-ers and home improvement enthusiasts. Come join the discussion about tools, projects, builds, styles, scales, reviews, accessories, classifieds, and more! Helping You to Do It Yourself!