Best solution:

Make a tool by welding a 17 mm nut onto a 12" piece of 1 x 1/8" bar
stock.  Grind the nut down if it's still too fat.  Just loosen the nut
with the tool and remove the plug with your fingers.

Quick and dirty solution:

Grab onto the exposed threads of the plug with a good sized pair of Vise
Grips. Really, you won't hurt anything but the appearance of the plug.

Even though I have a welder I've been using the latter method for many
years now, so I've never bothered to make the tool.

I'll take orders for them though if anyone wants one!

--
Stuart MacMillan
Seattle

'84 Vanagon Westfalia w/2.1
'65 MGB (Daily driver since 1969)
'74 MGB GT (Restoring sloooowly)

Personal mechanic for:
'70 MGB GT (Daughter's)

Assisting on Restoration (and spending OPM):
'72 MGB GT (Was daughter's, now son's)
'64 MGB (Son's)

Stripped and gone but their parts live on:
'68 MGB, '73 MGB, '67 MGB GT