ACROSS
1. <plant> SNOWDROP = SNOOP outside W(-in)D(-so)R
6. <alert> NOTIFY = (NOT I) + F(-acilit)Y 
9. GAINS outside R = GRAINS <cereals>
10/23. REMAINSIDES* = IN MEDIAS RES <without context>
11. <device> TUMBLE-DRYER 🡆 DERRY*
14. <cumbersome> UNWIELDY = U NW + ⭯YIELD⭯
15. <monster> SPHINX = (SPIN outside H) + X
17. SOLE MN = SOLEMN <august>
18. <easy> AMENABLE = A M ENABLE
19. <exemplar> POSTER CHILD = CLOTHSPIDER*
24. <passage> AVENUE = (-h)AVEN + U(-ndrinkabl)E
25. (-a)D(-d)E(-d) P(-a)T(-c)H(-e)S = DEPTHS <holes>
26. SENATORS* = TREASONS <seditious acts>

DOWN
2. ←IRON← = NORI <seaweed>
3. <one belted> WAISTLINE = →"LACED WINE"←
4. <closeness> RESEMBLANCE = EMBERS* LANCE
5. R→I, PARSLEY = PAISLEY <fabric>
6/22. ROGUEMENDER* = NOM DE GUERRE <wartime sign>
7. <drink> TODDY = ODD inside TY
8. FLATLY outside GRAN = FLAGRANTLY <without shame>
12. <advertise> DISSEMINATE = SITESMADEIN*
13. IN COMP LET E = INCOMPLETE <draft>
16. ADDRESS under HE = HEADDRESS <turban, perhaps>
18. <antiquated> ANCIENT = ACTNINE*
20. <bypass> SHUNT = SHUT outside N
21. <branch> BURN <set on fire>