Do As The Lady Says

This was a not-too-taxing offering from Franc, based on Lady Macbeth's familiar quote "Out, damned spot", which appeared unclued at 1A. Eighteen answers contained a jumble of the letters SPOT, which was to be removed before entry to the grid. The clues to the other answers each contained a synonym of SPOT, which was otherwise superfluous to the clue. It was interesting to see just how many different synonyms could be used; there are probably few words in the English language that could be treated in this way. What was also intriguing that in just a few cases the synonyms spanned partial words (e.g. 10D and 13D), making them rather harder to find. One wonders if this was a deliberate feature that just wasn't used very much, or whether it was forced by clueing requirements.

Across
1 See preamble (13, three words)
OUT DAMNED SPOT
11 Sounds harshly about Ring openings in embryonic form (7)
BLA[STOP]ORES (O inside BLARES)
12 Croat [witness] detailed upset with the bow (4)
ARCO (Jumble CROAT minus last letter)
14 Street light support: initially lowest among many politicians (4)
LAMP[POST] (First letters of LOWEST AMONG MANY POLITICIANS)
15 Gate [defect]? Not half normal! (3)
NOR (First half of NORMAL)
16 Listener, perhaps, is a set of pipes (5, two words)
ORGAN [STOP] (Two meanings)
17 [Smut] show in former Post Office (4)
EXPO (EX + PO)
18 Free international peace organisation (2)
UN[STOP] (UN = United Nations)
19 Reran chaotically to get [a little] closer (5)
NARRE (Anag. RERAN)
20 Deliberately light hill church [scene] (5)
TORCH (TOR + CH)
23 [Identify] anything making pair suffer setback (3)
OWT (TWO rev.)
25 Lance angry [blister] with space in sterile environment (9, two words)
CLEAN ROOM (Jumble CLEAN + ROOM)
38 Observe plant disease (3)
EYE[SPOT] (Two meanings)
30 [Character flaw] mentioned in broadcast at home with princess, but no new answer (5)
INDIA (IN + DIANA minus N(ew) A(nswer))
Gregson doesn't understand the definition here.
32 Drug for crazy people (5)
CRACK[POTS] (Two meanings)
34 Nowadays endorses (2)
AD[OPTS] (AD = Anno Domino)
35 In retrospect, oil can conceals whales' food [situation] (4)
CLIO (Hidden reversed in OIL Can)
36 Mad Irish [performance] poet (5)
RISHI (Anag. IRISH)
37 Follower's tipple (3)
A[POST]LE (Two meanings)
38 Lay beginning before numbers are up (4)
ANTE-[POST] (Two meanings)
39 Ships out of Cambodia [locate] fish (4)
EELS (KEELS minus K (Kampuchea = Cambodia)
40 Wind [predicament] troubled Elgar in opening of Gerontius (7)
GREGALE (Jumble ELGAR inside first two letters of GERONTIUS)
41 Bird spread insect haul before queen (13, two words)
[SPOT]TED FLYCATCHER (TED + FLY + CATCH + ER)

Down
1 Former pupil recently offered up [place] (6)
OBLATE (OB (old boy) + LATE)
2 Petitioning upper-class royalty mostly turned out (7)
[POST]ULATORY (U + jumble ROYALTY minus last letter)
3 Petruchio's [theatrical light]: not so inspiring (5)
TAMER (Two meanings)
...one being a reference to Petruchio in The Taming of the Shrew.
4 Oral digression? Dear Ophelia's content! (6)
A[POST]ROPHE (Hidden in deAR OPHElia)
5 [Perceive] candlestick could do one harm (7)
MENORAH (Anag. ONE HARM)
6 Feel great desire for ear[drop]? No? Not half! (4)
EARN (EAR + half of NO)
7 Stalactitic calcite's humming sound (5)
DRO[PSTO]NE (Two meanings)
8 Destruction of punk dance (almost) by gypsy [spy] (6)
POGROM (POGO minus last letter + ROM)
9 Nothing hurt old Caliph [Pip] (4)
OMAR (O + MAR)
10. T[rain intermittently] with English cricketers' practice session it's believed (5)
TENET (T + E(nglish) + NET)
13 Drawing of unusual [point]y acorn (6)
CRAYON (Jumble Y + ACORN)
18 Potted from [mark on snooker table], spun without use of top (5)
URNED (TURNED minus first letter)
21 [Trace] hat seen in church round lake (6)
CLOCHE (LOCH inside CE (Church of England)
22 Dinosaurs found in eccentric eras (7)
TRICERA[TOPS] (Hidden in eccenTRIC ERAs)
24 Summon small town (7, two words)
WHISTLE [STOP] (Two meanings)
25 [Zit] ended! Cleansed without covering bits in lanolin (6)
CEASED (CLEANSED minus L, N, i.e. first and last letters of LANOLIN)
26 Unfortunate [plight]! Toe broken round lace hole (6)
OILLET (ILL inside jumble TOE)
27 [Notice] rush to seal car in enclosure? The reverse (6)
CAREER (REE (enclosure) inside CAR)
28 Highly classified: Crete's in chaos (5, two words)
[TOP S]ECRET (Jumble CRETE)
29 Art [dilemma] in Enniskillen (5)
SKILL (Hidden in EnniSKILLen)
31 Sweetheart troubled? Had no [freckle]! (5)
DONAH (Anag. HAD NO)
33 Dickens' apple variety with flower that's not initially hardy (4)
RI[PSTO]NE (RHINE (i.e. river = flower) minus first letter of HARDY)
34 Toper's aid organisation's extremely shaky religious defection (4)
A[POST]ASY (AA (Alcoholics Anonymous) + first and last letters of SHAKY)