I myself have been collecting the tabs from slottafigures and metal sprues for years, but I've never come to the ungodly weight of 4 Kg! In fact, I've only got about 1/3 of a small plastic drawer in my 'bits wall' in almost 30 years of miniature painting...

Originally, I saved it all up because I thought I could use it when I would finally come around to casting my own minis. Which never came to pass, obviously.
But I have found a new use for them; weighing down bases. I tend to use washers as bases for a lot of projects these days, but there remains a sizable portion of miniatures that is based on plastic (slotta) bases.
And with some of the more expressive posing out there these days, it's often desirable to weigh down the bases as much as possible, so I glue those cut off slotta tabs to the bottom of the bases, which works really well.
In fact, I am painting a group of over 40 minis right now, that have all been weighed down in this fashion. They are plastics, but for the right heft, I even weighed down the ones that had no balancing issues...

So, if you can't get rid of your excess weight, just distribute it to your minis
