Hi
Using water with washing up liquid is a bad idea:
it'll effect the worms'taste and live-span and washing up liquid isn't very healthy to amphibians.
Better look for moist, grassy area's like meadows
or the lawn in your back-yard, best moment from dusk till dawn, especially when its raining.
Use a dung-fork,put it slantwise into the lawn
as far as possible and tap its stick regularly by hand. Be patient. When there are worms in the soil, they"ll crawl to the surface, frightened by the mole they expect to come. You just have to pick'm up. At some spot you'll find a dozen or two, at others a poor two worms. Electricity (strong battery) makes another way of luring the worms out but they"ll die within 10 minutes.
Han