Get a tub, preferably made of plastic, and large enough to fit in the goalies gloves you want to clean. You will need to soak the gloves in the tub. A tub of just the right size would work. However, a tub larger in size than necessary would work equally well.
Fill the plastic tub with warm water. Make sure that temperature of the water you are using is neither too high, nor too low. Dipping your hand in the water is an ideal way to check its temperature. If you hand does not get cold and does not burn either, temperature of the water is ideal for cleaning soccer goalie gloves.
Clean one glove at a time. Soak it in water for about 10 seconds. This is the time you would want to remove clumps of mud on the glove if required. However, you would need to replace the water because it would get muddy. After about ten seconds, remove the glove from water.
Now the actual cleaning process starts. Take a bar of soap and rub it up and down the thumb of the glove you are working on. Pay extra attention to dirty areas. If too much soap accumulates and you cannot see properly, dip and remove the soap and then resume as before. Continue in the manner until the thumb has been cleaned. Work with other four fingers of the glove in a similar fashion. Repeat the same process for the other glove as well.
After the cleaning process, allow time for the gloves to dry. You may have to use a towel to soak out the water. This can be done by placing one glove at a time in the centre of an old face towel, folding the towel in equal halves and then putting weight on top of the glove.
Store the gloves with palms apart after they dry. This will prevent the gloves from drying too much.