How to clean dried milk of magnesia on the inside of a bottle

[Bottleboy4419]

any idea? i tried to srub it with a tooth bush..i dont really wanna tumble it

 

[Bottle tumbler]

i just soak it for days in water, if that dont work try gas or kero

 

[Bottle tumbler]

when you get down to a little left in the bottle. put some bbs in the bottle about 1/4 filled and shake them around,
Not worth tumbling any way, flea markets $1 or less

rick