with mundo jungle being popular. here is the strongest start method / runes items

best runes on mundo jungle imo is definitely 29% attackspeed reds quints (since alot of damage is in that E . and attackspeed runes are very cost effective and mundo builds no other attackspeed items) 27 armor yellows 27 mr scaling blues

(the clear is easy without needing armor runes)

best build is cinderhulk. zzrot. warmogs. steraks. deadmans. im liking swiftness boots since they so cheap now

with this build. you are a huge splitpush power and you can walk up to towers and smack them with your E for a few seconds doing like 15% of a towers health, then just walk away when someone comes for you and heal with warmogs. save your ultimate as a escape method. and they cant stop you

repeat a few times and thats a dead inhib tower. dont even need to siege or teamfight. its just mundo baby

next. the steraks and massive tankyness means you can teamfight well if you want to anyway. but you dont even need to teamfight. you can be a splitpusher like udyr if you want too. nothing can stop you

now for the clear. the important part. i have found this to be the fastest clear this is the highest gold / most effective clear on mundo

start machete + 1 potion start E start red. smite it for health when its at half get Q next after red do krugs . kill the small krug then the big one. then shop for your talisman

skill order EQWQQR

then walk to gromp. kill gromp+wolves+birds+krugs . this will require no potions since you have talisman. skip your blue. its better to do blue when your higher level with completed jungle item. and if your enemy takes blue during all this it is fine, the gold/exp is not that much

then shop for your warding jungle item (i think its best) and clear your jungle again. after this clear your level 6 (or super close to it) and can start ganking if you want. its the fastest clear for mundo

if you wanna gank before 6 thats fine. however i find mundos clear is very fast using this method and your usually better off speedfarming 6 since you hit 6 before 7 minutes then u can start ganking

you dont need to buy health potions on mundo other than your first. all the clearing is easily done with no potions

oh. and grasp definitely best on mundo for masteries you want grasp. +4% health. tenacity or guardian. increased regen. increased 6% armor mr. the +12 river movement and 4% attackspeed. double edged sword. 2% lifesteal spellvamp. and bounty hunter those r best masterys for sure.