Across
American dullard needing month after school (5)
s i p (9)
Trick or treats possibly involving silver diadem ultimately (9)
I haven't cracked this one yet — but Fifteensquared have:
Anagram (possibly) of TREATS , containing AG (Ag = chemical symbol for silver, from Latin argentum ), then the last letter (ultimately) of [diade] M .
Some treat ended having you taken in? (5)
Recalled excellent comment about Southern European country (7)
I haven't cracked this one yet — but Fifteensquared have:
AI (A1 = excellent) + NOTE (comment), around S (abbreviation for southern), all reversed (recalled).
Merit shown by detective in series? On the contrary (6)
Trick husband with old guitar from America (4)
Big gardener’s treat being taken to stationery supplier (10)
Excessive on the other side? (10)
Uncovered guilt after returning around European place (4)
I haven't cracked this one yet — but Fifteensquared have:
[g] UIL [t] (uncovered = outer letters removed), reversed (after returning), around E (abbreviation for European). French-derived word for place, used in phrases such as “in lieu of” = in place of.
Trick a lecturer into temporary housing (6)
I haven't cracked this one yet — but Fifteensquared have:
A + L (abbreviation for lecturer), inserted into TENT (temporary accommodation). Trick = talent = a particular skill in doing something? I can’t quite think of a sentence where they could be interchangeable.
Nothing interrupting computer legend giving series of lectures? (7)
Auditorium associated with English orchestra in Manchester (5)
Depict one sneaky trick (9)
One’s little more than extra restraint: pound retained by one making expenditure (9)
I haven't cracked this one yet — but Fifteensquared have:
BIT (a restraint for a horse), then L (£ = abbreviation for pound sterling) contained in PAYER (one making expenditure). Bit player = an actor who plays a very small part, but still more than an “extra” (or “background actor”) who doesn’t usually get anything to say.
Scrabble piece capturing two-point score - feature of Spanish set? (5)
I haven't cracked this one yet — but Fifteensquared have:
TILE (a playing piece in the board game Scrabble ), containing D (a letter that scores two points in the game). The “squiggle” in the Spanish letter Ñ, which is indeed a feature of a Spanish Scrabble set: there is one Ñ tile as well as five N tiles.
Down
Group of nuns hide torsos in dressing (10)
Baronet coming in here with a healthy drink? (7)
I haven't cracked this one yet — but Fifteensquared have:
BT (abbreviation for baronet) inserted into HERE + A (from clue text).
Not initially promoting treat? (6)
I haven't cracked this one yet — but Fifteensquared have:
[t] OUTING (promoting = advertising), without the first letter (not initially). Outing = treat = a day-trip provided by a company for its employees, by a school for its pupils, or similar.
Badly using most of treat in a distinctive style (9)
Ready to defend maiden tucking into a wine (5)
I haven't cracked this one yet — but Fifteensquared have:
M (abbreviation for maiden, in cricket scoring) inserted into A RED (short for a red wine).
Request to get certain treat? (8)
Rigged 60% of trick - mine - for the time being (7)
Stop after start of trick or treat? (4)
I haven't cracked this one yet — but Fifteensquared have:
END (stop) after the starting letter of T [rick]. Treat = tend = provide medical care to.
After rewrite clue ending in ‘treat’? (10)
Exhibits regular bits of trick turning up in possession of a flash vehicle (9)
I haven't cracked this one yet — but Fifteensquared have:
SPORTS (wears, especially when referring to colourful or flamboyant clothes = exhibits), then alternate letters (regular bits) of [t] R [i] C [k] reversed (turning up = upwards in a down clue), containing (in possession of) A (from clue text).
Some believe the realignment is immaterial (8)
Inverted ribbon binding rubber feature of American uniform (7)
I haven't cracked this one yet — but Fifteensquared have:
TAPE (ribbon) reversed (inverted), containing ULE (rubber from a tropical American tree; a guess-and-check, but it’s in both Chambers and Collins). American spelling for what in British uniforms would be called an epaulette (shoulder decoration).
Core of trick I presented in twisted ancient language at the outset (7)
I haven't cracked this one yet — but Fifteensquared have:
Middle letter (core) of [tr] I [ck], then I (from clue text) inserted into LATIN (ancient language) reversed (twisted).
Treat kindly given to youngster: a doll (6)
Source of treat: whirling motion in lingerie item (5)
I haven't cracked this one yet — but Fifteensquared have:
First letter (source) of T [reat], then EDDY (whirling motion). A woman’s one-piece undergarment.
Apprentice devouring hot fish (4)
I haven't cracked this one yet — but Fifteensquared have:
CUB (apprentice, as in “cub reporter” = a trainee journalist), containing (devouring) H (abbreviation for hot).
Type letters or click words in the clue