My Mother would make these every summer when the cucumber patch came in. These are so good with fried potato's or just eating them by themselves. This is something both of my sons love to eat and ask each year for me to make them.
Take your sliced cucumbers, onions and green peppers and put in a clean gallon jar.
Put the sugar, vinegar, salt, celery seed, and mustard seed in the jar over the top of the veggies. This is fall to the bottom of the jar as well as stay on the pickles.
Put lid on jar and shake to get the mixture all through the pickles.
Refrigerate for at least 24 hours. Don't be alarmed when you look at them in the morning and there is only a 1/2 of jar. They will shrink over night. Shake jar before serving. The longer you keep them the better they will be.
They will last in the refrigerator up to a year. Which this never happens at our house.