How to Clean Bisqued Surfaces When Decorating with Underglaze Washes Underglaze washes add depth and character to a pot’s surface, but cleanup can leave it looking dingy. Never fear, a solution has been found: a kitchen’s companion, the Magic Eraser. Brooke Millecchia

Underglaze washes add depth and character to a pot’s surface by highlighting surface texture or pattern. But often the underglaze patina leaves the rest of the surface dingy or cloudy. Never fear, a solution has been found: a trusty kitchen companion, the Magic Eraser.

In today's post, an excerpt from the January 2020 issue of Ceramics Monthly, Brooke Millecchia shares her underglaze wash process and how to clean up after it with this magical cleaning tool. - Jennifer Poellot Harnetty, editor

As a potter, I often apply underglazes and other colorants to bisqueware. I love how they show off process marks and carved or added details, and bring out depth in the surface of the form. After color is applied, I wipe most of it away, leaving pigment inside the crevices and details. Sometimes that extra colorant clings to the surface, making the outside mottled and dirty. When this happens, I use the help of a Magic Eraser (a melamine-foam cleaning sponge). It erases unwanted color and makes my work clean and crisp!

The Process

Before you begin, gather the supplies you’ll need (1). On a clean surface, place a bucket of water, your bisque-fired pots, a melamine-foam cleaning sponge, scissors, a standard round studio sponge, a paint brush for underglaze application, waterproof 220-grit sandpaper (I use 3M brand), and your choice of colorant (I use Amaco Jet Black Velvet underglaze).

Working one piece at a time, fully submerge the bisque-fired pot in the bucket of water and remove it (2). Grab the sandpaper and dunk it in the water as well. While standing over the bucket, begin lightly sanding the surface of your pot until it’s smooth (3). Feel free to dunk the sandpaper in water as often as needed. I find it easier to sand if the paper is really wet. For reference, I spend about 1–2 minutes sanding a standard-sized cup. When your pot is smooth, remove the sanding residue with a damp sponge until clean. Be sure to only dunk the pot once. Colorants won't cling to the surface if your pot is waterlogged. 

Next, add a light wash of underglaze or oxide to the areas you want to enhance (4). I mix my underglaze with a little water to make it the consistency of milk. Watering it down allows the underglaze to easily seep into the deep crevices, such as handle attachments and intricate surface carvings. It also makes pigment removal easier and gives your sponge a longer life. Plus, less underglaze ends up down the drain. When you’re finished painting a light, even coat, remove the unwanted underglaze with a damp studio sponge (5), making sure to rinse the sponge often. Doing this keeps the undesired colorant off the surface of your pot.

Using scissors, cut the melamine-foam cleaning sponge into four equal parts (see 6). Each quarter should clean a handful of pots, depending on size, clay, and pressure used. When your sponge starts to break into pieces, throw it away and grab a new section. Wet one of the sponges, squeeze out excess water, and begin gently wiping away excess underglaze (6). Rinse the sponge often. Notice the difference between the right and left sides of this teapot (7). It takes less effort using the melamine-foam sponge than the studio sponge to remove the colorant, so be careful as the sponges are fragile and have a fairly short life. Once the bisque-fired surface is free of residual color, proceed with your normal steps to completion. Rinsing is not necessary. For best results, work through each step, one pot at a time. The moisture in the pot helps with the process. Good luck!

the author Brooke Millecchia is a studio potter and instructor based in Upstate New York. Her work is available through a handful of galleries, including Gandee Gallery in Fabius, New York (www.gandeegallery.com). To learn more, visit www.brookemillecchia.com and Instagram @brookemillecchia_ceramics.

**First published in 2020.