Theme: It's all hush-hush _ I can't tell you anymore; I'm sworn to secrecy.
18A. Grand Prix series designation : FORMULA ONE. Secret Formula (Every product has one.)
23A. Controversial Vietnam War defoliant : AGENT ORANGE. Secret Agent Song(3:05)
37A. Avon or Fuller Brush work, e.g. : DOOR TO DOOR SALES. Secret Door. Song "Green Door"(2:15)
52A. What Al Capone led : LIFE OF CRIME. Secret Life. Walter Mitty had one.
58A. "Shh! Don't tell!" and hint to what can precede the starts of 18-, 23-, 37- and 52-Across : IT'S A SECRET
Argyle here; that's no secret. No secret the grid spanner is a dying occupation. Marti, any secret insights on the puzzle's construction.
Across:
1. "Say it isn't so!" : "OH NO!". The "Say It Ain't So, Joe" story was most likely not true.
5. Slick : OILY
9. Japanese poem with 17 syllables : HAIKU. so limericks today take a backseat to haiku will they entertain
14. More than simmer : BOIL
15. Natural skin soother : ALOE
16. Caravan stop : OASIS
17. '50s-'60s Ramblers, briefly : AMCs. (American Motors Corporation)
20. Brings in, as salary : MAKES
22. Geeky types : NERDS
26. Onetime Leno announcer Hall : EDD
29. Salt, in France : SEL
30. "__ we there yet?" : ARE
31. Add to the staff : EMPLOY
33. Serving at Popeyes : BREAST. Which piece?
36. Gutter site : EAVE
42. Too : ALSO
43. Country bumpkins : YOKELS
44. "I hope you've learned your __!" : LESSON
47. Pro vote : YEA
48. Little white lie : FIB
51. "__-hoo! Over here!" : YOO
56. Collar attachment for Spot : ID TAG
57. "MASH" setting : KOREA
63. Cheesy sandwich : MELT
64. Dance in a line : CONGA
65. Actress Garr : TERI
66. Autobahn auto : AUDI
67. Like a truck climbing a steep hill : IN LOW
68. Flower part : STEM
69. Tiff : SPAT
Down:
1. White House family : OBAMAs
2. Respect that's "paid" : HOMAGE
3. Coin with a buffalo, once : NICKEL
4. Designer Mary-Kate or Ashley : OLSEN
5. Klutzy fellow : OAF
6. U.N. worker protection gp. : ILO. (International Labour Organization)
7. Doone of Exmoor : LORNA. Lorna Doone: A Romance of Exmoor is a novel.
8. Red Sea republic : YEMEN
9. "Texas" poker variety : HOLD'EM. A little search thru the TV channels should turn up a game.
10. Very small batteries : AAAs
11. Prefix with metric : ISO. (isometric)
12. Kith and __ : KIN. Friends and Relatives
13. Exploit : USE
19. Hankering : URGE
21. Button that gets things going : START
24. Sandwich cookie : OREO
25. Raring to go : READY
26. Airline with famously tight security : EL AL
27. Symbol of peace : DOVE
28. Hair colorings : DYES
32. Vegetables in pods : PEAS
33. The "B" in TV's former The WB network : BROS. (Warner Bros.)
34. "Your point being ... ?" : "SOO...?" The "what" is implied.
35. Target city for Godzilla : TOKYO
37. Tyne of "Judging Amy" : DALY
38. Margarine : OLEO
39. __ buco: veal dish : OSSO
40. Scuba diving area : REEF
41. Not tight : SLACK
45. Familiar adage : OLD SAW
46. Evening, in ads : NITE
48. Inflame with enthusiasm : FIRE UP
49. Marcos with a shoe collection : IMELDA
50. "Take a hike!" : "BEAT IT!"
53. Verifiable findings : FACTS
54. "Snowy" wader : EGRET
55. Sauce tomatoes : ROMAS
56. "Othello" conspirator : IAGO
58. Here, in Le Havre : ICI
59. Truck weight unit : TON
60. NBC late-night comedy hit : SNL
61. Before, in poetry : ERE
62. Tiny Dickens boy : TIM
Argyle
