If this doesn't make sense,get some gas into a bottle.

If you got this far without talking to Menderbot about rust on the row-bot, here's how that conversation goes. (This guide assumes you picked upthe sponge in the mines.)

<Menderbot> [How Can I Help You, Niko?]
<Niko> The boat robot is rusty and it told me to ask you about it!
<Menderbot> [Oh.]
<Menderbot> [...........]
<Menderbot> [I'm Still Too Busy With Patching The Place Up, But The Solution Is... Well... A Simple Solution.]
<Menderbot> [You Just Need To Mix Some Of The Same Jelly You Used To Manufacture A Replacement Battery With Some Gas.]
<Niko> So I just-
<Menderbot> [You Can Get Gas From The Gas Bot In The Room To The Right Of The Elevator Room.]
<Niko> Uh...
<Menderbot> [You Already Have A Sponge, So That's Good.]
<Menderbot> [And Please Use Protective Gear When Handling The Solution.]
<Niko> Wait but-
<Menderbot> [There Should Be Gloves In The Storage Room.]
<Menderbot> [Safety Goggles Should Be In The Lab.]