D.C. Mun. Regs. tit. 9, § 402
402.1 Casual and isolated sales under § 128(h) of the Act mean sales of an unplanned and non-recurring nature that are made by an individual or an organization which finds it necessary or desirable to dispose of certain items or tangible personal property originally acquired for the person's or organization's own use or consumption.
402.2 Examples of casual and isolated sales include, but are not limited to, the following:
402.3 The gross receipts from the sales of food, meals, greeting cards, magazine subscriptions, novelties, toys, jewelry, wearing apparel, household appliances, and other items purchased or acquired by semipublic institutions (such as churches, religious, scientific, and educational organizations or institutions) and by social, fraternal, and benevolent organizations and other organizations or institutions of a similar nature, for the purpose of resale at planned or organized functions, affairs, or campaigns (such as bazaars, luncheons, dinners, suppers, antique shows, rummage sales, house-to-house campaigns, and similar activities) are not considered to be casual and isolated sales and are subject to District sales tax.
SOURCE: Administrative Ruling No. 2, 16 DCRR.