As you work, you are likely to have a number of scrap pieces of clay accumulate. This is true of hand building, and even truer of throwing. In hand building, if the scraps haven’t dried out too much you can re-work them without having to do much more than compress them back together and work the air out. If you are throwing, however, your scraps are likely to be quite wet and will include slurry.
Don’t throw these scraps away; you can recycle them back into usable clay again.
The first thing to make note of is that like should go with like. This is especially important in regards to the clay bodies’ maturation range. For example, scraps of low-fire clays should only be mixed with scraps of low-fire clay. Other similarities you may want to sort by include working characteristics (throwing clays vs. hand building clays) and color.
White clay bodies, if you want them to remain white, should only be mixed with other white clay body scraps of the same temperature range. You will also want to make certain that the bucket, towels, working surfaces, and tools used are all clean and free of other clay bodies or ceramic colorants.
I keep separate, marked scrap buckets for each clay body I work with. That way, I can easily keep track of which clay body is where.
When your scrap bucket is half way full, discontinue putting new scrap into it (switch to a new bucket for new scraps). Allow the scrap clay to dry completely, which may take several days to over a week. Make sure that any large pieces are broken into bits. Smaller pieces will slake down faster and more thoroughly than large chunks.