firefox eats linux mint /home memory : 
Seems Firefox browser uses disk memory. Computer have crashed many times and was eaten some 4GB of memory, approx 100-500Mb each time. 

I believed, it was php script, as in this question

https://stackoverflow.com/questions/60065930/nested-php-loop-eats-gigabytes-of-linux-mint-memory

But, now i have found that 3D javascript examples from plotly and echarts eats a lot of memory too. 

Seems the Firefox browser is the reason, as it crashes when script is running. 

How to recover the lost memory? 
I can not copy more files from /home .