Solutions :

3-letter words (1 point): 60

AID; AIR; AIS; BON; BOT; BRR; BRU; BUD; BUM; BUR; BUS; BUT; DIS; DUB; DUI; EMO; EMU; ERR; IDE; IRE; MEN; MET; MOB; MON; MOT; MUD; MUS; MUT; NET; NOB; NOM; NON; NOT; OBS; ONE; RED; RIA; RID; RUB; RUD; RUM; RUT; SAI; SAU; SIR; SUB; SUD; SUI; SUM; SUR; TEN; TOM; TON; TUB; TUI; TUM; URB; URD; URE; UTS.

4-letter words (1 point): 76

AIDE; AIRT; AUTO; BONE; BOTS; BRED; BRER; BRIS; BRUS; BRUT; BUDI; BURD; BURR; BUST; BUTS; DERM; DIRE; DIRT; DISA; DRUB; DRUM; DUBS; DUMB; DURE; DURR; DUST; EMUS; IRED; IURE; MENO; MENT; MOBS; MOTS; MOTU; MUID; MUIR; MURE; MURR; MUST; MUTS; NOBS; NOME; NONE; OMBU; OMEN; RIAS; RIDE; RUBS; RUDE; RUME; RUSA; RUST; RUTS; SAID; SAIR; SAUT; SIDE; SIRE; STOB; STUB; STUD; STUM; SUID; SUMO; SURD; SURE; TOMB; TOME; TONE; TUBS; TUIS; TURD; TURM; UMBO; URBS; URDE.

5-letter words (2 points): 52

AIDER; AIRED; AIRER; ASIDE; AURIS; BRIDE; BRUME; BRUST; BRUTS; BUDIS; BUIST; DIRER; DRUBS; DUMBO; DUMBS; EMBUS; EMURE; METRE; MONTE; MOTUS; MUDIR; MUIST; MURED; MURID; MURRE; MUTON; NOMEN; NONET; NOTUM; OMBRE; OMBUS; REDIA; REDUB; RIDER; RUDER; RUMBO; RUMEN; SIDER; SIRED; STONE; STURE; STURT; SURED; SURER; TENON; TOMBS; TRIDE; TRIST; TRUST; TURBO; TURME; UMBRE.

6-letter words (3 points): 18

AIRBUS; AIRMEN; ASTONE; AURIST; BURRED; DERRIS; EMURED; METRED; MONTRE; MURDER; REDIAS; REDUBS; SAIRED; SAIRER; SIRRED; SUBMEN; SUBNET; UREDIA.

7-letter words (7 points): 8

AUTOMEN; DISTOME; DISTURB; ENTRIST; ENTRUST; METRIST; MONTURE; SUBTONE.

8-letter word (11 points): 1

RUBSTONE.