Summarize the problem

I need help removing rusted screws from an outdoor outlet box. A few notes:

  • The outlet box was used for an outdoor light that I removed
  • I turned off the breaker
  • I have access to the back of the box

Provide details and any research

Here's a photo of the box: enter image description here

When appropriate, describe what you’ve tried

I've tried:

  1. Applying WD-40 Specialist Penetrating oil
  2. Hammering the front and sides of the screw
  3. Trying and failing to unscrew both screws

My questions are:

  1. Should I try other things to remove the screws?
  2. Or should I just pull the box out and install a new one?
  • 8
    If you can get the box out then replace it, not worth the headache for $3.00 box.
    – Alaska Man
    Commented Jan 3, 2021 at 22:20
  • An "impact driver" screwdriver. You stick the bit into the screw and hammer on the driver.
    – Hot Licks
    Commented Jan 4, 2021 at 2:29
  • Do you have a T-handle screwdriver? They can be surprisingly more effective than an ordinary screwdriver. Commented Jan 4, 2021 at 12:35
  • Have you tried heating up the screws? They make heat guns for this purpose, but you might have luck with a regular hair dryer. Be careful not to melt the plastic of the box though. I've even seen a blowtorch used to get rusted screws out, but you really gotta know what you're doing with those. Commented Jan 4, 2021 at 16:41
  • 1
    Many good answers in this thread. I purchased a set of pliers with designed for this that have proven quite good in the times I have used it. The score marks on the tips are opposite of most pliers, allowing the grooves to dig into the head in order to turn.
    – Evil Elf
    Commented Jan 5, 2021 at 12:53

11 Answers 11



If you saw thru the rusty plate (twice, one for left slot and one for right) and remove it by pulling it out from under the screw, the remaining screw will be sticking up enough for you to get hold of the whole head with a pliers and unscrew it.

It is hard to argue w Alaska Man (or you) re merits of replacing the whole box. But it seems like you would need these screws out to do that too.


WD-40 is NOT a good penetrating oil. Liquid Wrench is better, but still not that great. The best kinds are called Kroil or PB Blaster, you can find them in auto parts stores. But if you don't have an auto parts store nearby, wintergreen oil can be bought at many drug stores and is much much better than WD-40 or Liquid Wrench. With a good penetrating oil you put it on, let it soak and tap it gently to work it in for a few minutes.

  • 6
    WD-40 Specialist Penetrant (what OP used) is not the same as plain WD-40 (what this answer seems to have misunderstood OP to have used).
    – J...
    Commented Jan 4, 2021 at 12:32
  • @J...yes we get the same problem on Bicycles.SE where some claim using WD40 is fine, but there's confusion over the plethora of products marketted under the brand name "WD40" which are completely different products.
    – Criggie
    Commented Jan 4, 2021 at 19:17
  • Cut strip in middle.
    Bend each part and use as a "spanner" to friction turn the screws while also applying torque to the screws. Having three arms or a helper makes this easier. Once you have even slight screw movement a vice-grip can grip the heads.

  • Filing flats on opposite sides of a screw head make it much easier to grip them with a vice-grip, even when they are in their original position.

  • Drilling off the heads with a drill somewhat larger than the screw shaft diameter will remove the heads with minimal damage to the strip - which you may well wish to replace in any case :-).

  • As others have mentioned, impact drivers can work magic.

In that location better waterproofing and a better-galvanised strip are in order.


Try using an impact driver , the other rusted screw may shear off though , judging by its condition.

I'd opt replacing the box , as its too much headache to fix. If you do get it out, try adding antiseize next time to the screws or getting a box that has a better design regarding screw placement and water entry (ip rated waterproof/outdoor gpo?) or even getting a high grade stainless fastener (same screw size/thread pitch as existing) so it doesn't rust.


The box looks like it is plastic, so if you can get a good grip on the screws, they should be able to be forcibly removed.

You could start with the impact driver, then the ole Dremel a deep slot in the top, and if that fails, I like Willk's suggestion of hacking (or cutting) out the crossbar to get more access to the screw head. A vice grips should work then.


I once removed a really badly rusted screw with a pair of locking pliers (AKA mole wrench, vice grip).

I'd tried penetrating oil, big screwdrivers including an offset screwdriver, and (if I recall) using some impact, all to no avail, and I didn't hold out much hope — but the mole wrench got it turning fairly easily.

So if you have one of those, it's well worth a try.  (And if you haven't, it's worth getting one and then trying!)


Since it is a plastic box I would grab the screw head with locking pliers ("vice grips") literally as tight as possible, and try to turn it out. This should be able to force the screw to turn in the plastic, despite the rust.

I would recommend not removing the box until you've exhausted other possibilities. The cost of the new box is not the issue, but it could take a surprising amount of effort to get a new box in there in the right position, flush, and secure. Boxes are not identical in size / shape and it obviously is fitting into masonry which was built to exactly fit the old box.

That said, if you do replace the box look for a new one that is smaller so you don't have to modify the masonry. But the box is most likely secured only by the masonry, not screws etc.

A smaller box could be initially wedged in place using shims (which can also be purchased) and then possibly just secured with generous amounts of exterior construction adhesive.

Also, since there is obviously a water issue you should try to address that. Another plastic box may be a good choice, but that doesn't eliminate the source of the water. You may be able to add some caulk and / or weatherstripping material to the outlet plate that could keep out some amount of water.

(There are outlet covers that are designed to be weathertight, but that alone doesn't prevent water from getting between the cover & the box.)


I had good luck with Rustoleum rust dissolver (gel).


The tool designed for the job is a screw extractor

enter image description here

You can get these from most hardware outlets. They're handy to have in your toolkit.

Here's a detailed explanation:


There are plenty of videos online, just search your favourite video site for screw extractor

  • 4
    I don't think they would make them if they didn't work, but I have never been able to get one of these to work for me.
    – BlackThorn
    Commented Jan 4, 2021 at 23:47

Use a flat head screwdriver; that will probably work. If you can't get any leverage, use pliers to get more leverage on the screwdriver.

Good luck!


heat is the best cure. hear. heat gun or tiny torch Propane, just on the #6 tiny screw head easy outs will fail on any case hardened screws seen here, Vice grips(tm) and heat, the heat makes the plastic soft and the screw 10x more easy to turn and not snap it in half, the 1 thing to avoid. I see the box is MORTAR in, so that is last never first, a new box. like this.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.