Theme: Show Me the Money - The unifier instructs us to put CASH before the last word of the starred entries.
18A. *Duplicator in an office : COPY MACHINE. CASH MACHINE aka ATM.
24A. *Great Chicago Fire scapegoat : MRS. O'LEARY'S COW. CASH COW brings in a very high profit margin. Down on the farm, the cash cow not only produced a lot of milk but the milk had a high percentage of cream, where the real money is.
39A. *Classic chocolate treat : MARS BAR. CASH BAR, magic words on any reception notice. (My mistake, it is OPEN BAR we like to see!)
49A. *Take a path of least resistance : GO WITH THE FLOW. CASH FLOW - May yours never be negative.
60A. Seller's assurance of payment, and a hint to what the last words of the answers to starred clues can have in common : CASH UP FRONT. PSA: You should never give CASH IN ADVANCE for any online claim that you have money coming to you.
Argyle here. Typical Tuesday. Some names that are gimmes to some and unheard of by others. Some mild misdirection but four solid themes. All-in-all, a good continuation of the week.
Across:
1. The NFL's Montana and Favre, e.g. : QBs. Football quarterbacks.
4. __-wip: "real cream" brand : REDDI. The stuff in the can.
9. Rap's __ Rhymes : BUSTA. This gent.
14. Suffix with script : URE
15. Apply, as pressure : EXERT
16. Not cool, man : UNHIP
17. Marksman's skill : AIM. I'm not happy with this answer. Anyone can aim, the marksman can hit what he aims at. The answer needs a modifier, like 'steady aim', to be a skill, IMO.
20. Former boxer Ali : LAILA. She is the daughter of boxing legend Muhammad Ali.
22. Musician's gift : EAR
23. Makes a decision : OPTS
28. Apt. complex unit : BLDG.
29. Ohio rubber city : AKRON. Four major tire companies, Goodrich Corporation, Goodyear Tire and Rubber Company, Firestone Tire and Rubber Company and General Tire, were headquartered in the city.
32. Canonized Fr. women : STEs
35. Grand Coulee, for one : DAM
37. Thief-turned-sleuth Lupin : ARSÈNE. Unknown to me; a French rival of Sherlock Holmes.
38. Nonpro sports org. : AAU. Amateur Athletic Union.
41. "Proud Mary" pop gp. : CCR. Creedence Clearwater Revival.
42. Throbs : PULSES
44. Watchdog's warning : "GRR"
45. Prog. listing : SKED. Sked is shortened version of the word schedule and often isn't indicated as a abbreviation as it is today.
46. Spot on TV : PROMO
47. Aptly named fruit : UGLI
56. Narrow cut : SLIT
58. Filmdom's Farrow : MIA. First gained wide acclaim for her role as Allison Mackenzie in the prime time soap opera Peyton Place.(1964)
59. Short vodka order : STOLI. Stolichnaya, but it is also trademarked as Stoli.
64. Sewing kit item : PIN
65. Starts the pot : ANTEs
66. Army base near Petersburg, Va. : FT. LEE
67. 12/24 or 12/31 : EVE
68. Iraq's main port : BASRA. Even though it is 34 miles from the coast. Map.
69. Ritual celebrating the Jews' liberation from Egyptian slavery : SEDER
70. __ Moines : DES. Iowa, "American Heartland".
Down:
1. Uneasy feeling : QUALM. Good word. Germanic?
2. Prickly bush : BRIAR
3. 18-wheelers : SEMIS
4. Automaker's bane : RECALL. Haven't had any lately.
5. Lead-in for skeleton : EXO
6. Bank statement abbr. : DEP.osit
7. Laundry appliance : DRYER
8. "Be that as __ ..." : IT MAY
9. Tampa Bay athlete, briefly : BUC
10. Opens, as a gate : UNHOOKS
11. Marine salvage crew's job : SHIPWRECK. It used to be the big job was bringing up the treasure; now it is keeping possession once it's up.
12. Glass darkener : TINT
13. Big galoots : APES
19. Latin art : ARS. You might find this interesting.
21. Throws softly : LOBS
25. Old Norse works : EDDAs
26. Biochemist's gel : AGAR
27. Singer Vikki : CARR
30. "... __ and for all!" : ONCE
31. Bookish type : NERD
32. '90s-'00s NFL Pro Bowler Warren : SAPP. He played for the Tampa Bay Buccaneers and the Oakland Raiders.
33. Bull: Pref. : TAUR
34. Speakers at memorial services : EULOGISTS
36. Chow mein additive : MSG
37. "I can't believe this!" : "AARGH!"
39. "Feed me," in Siamese? : "MEOW"
40. Champagne word : BRUT. Very dry.
43. Cover completely : SMOTHER
45. Prepare, as flour : SIFT
48. Red Sox pitcher Jon : LESTER. LaLa Linda, care to comment?
50. Brat : IMP
51. Little fights : TIFFS
52. Bret who wrote gold rush stories : HARTE
53. Ran with ease : LOPED
54. Fruit yielding oil : OLIVE
55. Some cellar contents : WINES
56. Union underminer : SCAB
57. Head-turning Turner : LANA. Back in the day. Image.
61. Mex. neighbor : USA
62. Trite : OLD
63. Originally called : NÉE
Argyle