ACROSS
1. Drifting on air
5. South American nation
9. Canny
12. Naps
16. Whip (yolk)
17. Tartan cloth
18. Revise
20. Frozen block (3,4)
22. Havana product
23. Submit
24. Wireless crackle
26. List of topics
27. Payoffs and kickbacks
28. Sock mending tool (7,6)
31. Unbending
32. Reclaim
34. Bordered
36. Kangaroo pouch
37. Deep thinker
40. Printing fluid