1: Tossed sixth of cookies in class (5)
4: Like Nadia or Olga, my acting's affected (9)
9: He is found in the alloy described (5)
10: Delicate stem is enlightening (5,4)
11: Thirteen broken adzes repaired (6,5)
12: Polygraph unexpectedly traps vandal (3)
13: Examine good-looking man? Yes! (5)
15: A short bird-man climbed in Africa (7)
17: Dance to old home recording (3 4)
19: Belonging to you, is getting to me, Herb (5)
21: Throw out faulty nib (3)
23: Inspects old radical for a moment (5, 6)
25: 16-down Redundant RE question, like derr (2,3,4,1,8)
26: Feed all but the first stranger (5)
27: Plantation divided by one true sign of trouble (4,5)
28: Challenged Ruby after district attorney (5)