Greta Garbo — the legendarily reclusive actress who refused to sign autographs or give interviews — would have had “mixed feelings” about an auction next month of 800 of her possessions, says her great-nephew Derek Reisfield. (Since Garbo reportedly burned sackfuls of fan mail unopened, “mixed” may be an understatement.) But Reisfield was heard saying aboard the Queen Mary 2, where he previewed some auction items, that Garbo’s family views the auction as a way to show what she was really like — especially her sense of humor that wasn’t seen by her adoring public. Among more whimsical possessions to be sold on Dec. 14-15 by Julien’s Auctions in Beverly Hills are skis, leather driving caps, caviar spoons, swimsuits, a cocktail shaker engraved with the initials “GG” in Garbo’s handwriting and holiday decorations including a blow-up plastic snowman. Reisfield gave a talk about Garbo at sea and revealed that she hadn’t originally intended to retire when she moved to New York after her final film in 1941, hoping to return to the screen after World War II. Garbo reportedly wanted to make a version of “The Picture of Dorian Gray” co-starring Marilyn Monroe — but never did.