обмылок
Муж.; разг. remnant of a cake of soap, remaining piece of a bar of soap; мн. washing, soap-suds м. разг. remnant of a cake of soap.
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Полный русско-английский словарь
на Gufo.me
Муж.; разг. remnant of a cake of soap, remaining piece of a bar of soap; мн. washing, soap-suds м. разг. remnant of a cake of soap.