Space your containers about one half inch apart so that air may flow between them. Containers too close together can cause slow uneven cooling, resulting in a poor candle surface quality and frosting.
Washing or dry wiping is unnecessary and not recommended unless your container is dirty or unless washing or dry wiping is recommended by your container manufacturer.
As a general rule, try to achieve a full burn pool of 1/4 to 1/2 inch deep, from side to side in about the same number of hours as the number of inches the diameter of the container. For example: An Apothecary jar with a diameter of 4 inches should achieve a burn pool depth of 1/4 to 1/2 inch, side to side, within about 4 to 5 hours. Too large of a wick will produce deeper, quicker burn pools but may also cause sooting and short burn times.