I saw a dramatised production of Jane Austen's Mansfield Park at the theatre last night, and someone in it mentioned 'sponging'. The word seemed slightly incongruous and anachronistic to me, but I checked the full text online when I came home, and it does appear (in Chapter 10) with reference to Aunt Norris:
"What else have you been spunging?" said Maria, half-pleased that Sotherton should be so complimented.
"Spunging, my dear! It is nothing but four of those beautiful pheasants' eggs, which Mrs. Whitaker would quite force upon me: she would not take a denial...."
Spunging was a common spelling up to the 18th century. The verb 'to sponge' dates back to the 14th century, but originally it just had the sense 'clean with a sponge'. The sense 'To get from another in a mean or parasitic manner' (OED), dates back to the second half of the 17th century, a good 140 years or so before Mansfield Park was written.
Interestingly, the first citation for sponge-cake (1808) in the OED is from a letter of Jane Austen to her sister Cassandra: " You know how interesting the purchase of a sponge-cake is to me".