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I have two screws holding on the metal disc covering the shower drain. Neither appears to be stripped. I would like to remove these screws to clean out the drain.

The problem is that the screwdriver won't go into the slots. I think there's some calcium buildup on the screw heads. I tried lightly scratching it with my screwdriver, but the stuff is really on there. I don't want to strip the screws by forcing too hard.

Is there a quick way to dissolve the calcium off the screw heads? Hoping that I don't need to go out and buy a jug of CLR for something so small.

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You'll find other uses for CLR. Buy it today and use it for years. – BMitch Aug 6 '12 at 13:38
Now that the drain cover is off, I'm thinking CLR isn't a bad idea. – dangowans Aug 6 '12 at 13:50
up vote 3 down vote accepted

Most of the time you can chisel it out with a scratch awl and a utility knife. You will dull the blade of the knife, but that's why they are replaceable. I also would use my $2 awl, not the heirloom one with the rosewood handle.

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The scratch awl idea got me started. I ended up using a smaller screwdriver, and lightly tapping it with a hammer. The calcium slowly broke up, and I was able to get the screws off. Thank you! – dangowans Aug 6 '12 at 13:46
Once tools are expendible, they take on all kinds of new uses. I have done exactly the same as you did. (That wasn't your great grandfather's favorite screwdriver, right?) – bib Aug 6 '12 at 13:56
I also save my utility knife blades for recycling/these types of tasks. – Wayne Werner Aug 6 '12 at 16:18

an old knife or a utility knife without those snap blades should help you cut into whatever it is. alternatively run along the slot with a drill with tiny drillbit attached. vinegar helps decalcify. it might take many applications though. it should bubble a tiny bit if the gunk is indeed mostly calcium or another base mineral.

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Thanks for the vinegar tip. Now that the drain cover is off, I'm seeing the tiny bubbling on the white material. – dangowans Aug 6 '12 at 13:47

I've never found anything that gets rid of calcification on screw heads very well, I've had better luck in the past digging it out manually. I'd use something expendable like the point of a metal barbecue skewer, or even the end of a coat hanger squished into a wedge.

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