I've just bought a second hand road bike. Everything works fine except that I can't get take the front wheel off.

The quick release lever opens and closes fine, but the front dropouts have lawyer lips on them and the quick release doesn't open wide enough to clear them. I need to loosen the cap on the other end of the skewer further but it will only jiggle back and forth a tiny bit and not actually unscrew.

I've tried using regular oil to no avail. Other than resorting to WD40, is there anything else I can try?

Penetrating oil may also help, it's much thinner than WD-40 and can get into the threads more easily.

Are you saying the nut on the other side of the lever doesn't turn properly to loosen it? If worse comes to the worst, you could try cutting the nut/axle with an angle grinder to get it off and replace the skewer. Destroying the skewer is probably the cheapest option.

Yeah, it's the cap on the other side of the skewer. It does turn ever so slightly in both directions, but it is a microscopic amount. Not sure there would be enough space to get to it with an angle grinder though.

grab the non-lever side with a pair of pliers and turn the lever counter clockwise. If it is too rusted to come off, then you will probably need to destructively remove it and get a new skewer.

I have had luck just grabbing both sides of the skewer with vice grips and twisting them apart.

When you do get it off, grind\file off the stupid lawyer lips.

I just hack-sawed off a QR skewer, the Rust required it.

IF its a Disc Brake Front wheel , live with the retention tips , there .

Front wheels can work out of the drop-outs when you put the brakes on.

there are long throw QRs to get a quicker wheel change,

or, make it more convenient if you take your front wheel out,
every time you lock up the bike.

clix skewer?

Just curious, why do they call them lawyer lips?

The reference to "Lawyers" is due to the perception by manufacturers, that they need to provide ample warning and safety mechanisms to prevent the wheels from falling out of the drop-outs should a fastener be less than optimally secured. The extra lips on the fork (or sometimes retaining washers) are commonly added to bikes to keep the wheel inside the fork, so that in a court of law, if someone sues, they can't argue that the product has a bad design that allows the axle and therefore wheel to drop out and therefore cause injury. Which is why most new bikes all have vertical dropouts these days for the rear, and many front forks have "Lawyer Lips".

Lawyer lips are a safety feature that help prevent accidental injury when riding with an improperly/inadequately tightened skewer.

And I much appreciate vertical dropouts.

I recently found a frame without them. Now I actually pay attention to how tight I make things haha.

Hate when I have to pay attention to stuff.

It should be emphasized, with the increasing # of leisure/cross bikes with disc brakes that the torque the disc applies to
the front axle can pop the axle out of the slot, even reasonably well clamped by the QR, hence the retention 'lips' are
mandatory with disc brakes. Rim brakes do not do this.

with a left rear of the fork blade, mounted disc caliper, there is a new secondary Torque Center
when that brake is applied, the wheel then functionally rotates around that new torque center.
its that force vector, that pushes the axle out of the dropout.

additional changes that combat that , forks with forward opening dropouts.
and a fork that puts the disc caliper on the leading side of the right fork blade
and thru axle forks without any dropout at all.

Managed to get the nut off! Used a pair of vice grips as suggested and some brute strength. Lots of water and rust, and it appears the threads at outer end of the nut have been stripped (is this common with Campagnolo skewers?) Thanks everyone for your help.

(Have another problem with the headset though, but that's for another post.)