I can't make sandbags from Milliput to save my life, any tips or help on how to make something that doesn't look like chewed up bubblegum?

milliput loves water. have a dish of water at hand, wet your fingers. That will make all the surfaces smooth. Squish em out like watermellon seeds.

I think I found one problem, after reading this link I think I bought stale milliput

Apologies if links to other sites are not allowed.
http://www.scalemodelguide.com/construction/techniques/techniques-uses-milliput-putty/

My putty is extremely hard and has a crust, makes for uncomfortable jagged pieces when kneading.

Damn this stuff isn't cheap either.

Cut away the crust before measuring and blending. that is waste. If it is too firm add water.
I have been using the same package of milliput for about four years.

That helped tremendously! I fairly happy with the outcome, I think I'll snap a couple pics.

Appreciate the tips

yup. I think youve got it.