I once had the same problem with a gallon of old gas mixed with oil from a two cycle engine. It took awhile but it worked. Gas is very subject to evaporation. I poured it into a flattish but large pan, plastic would work, and just left it. It evaporated slowly but it is gone. Four gallons left in an open container, maybe a dish pan, would work. I left mine in a backyard shed, maybe you could leave it in a safe corner of the garage.

No phone number I called the fire department NON emergency number, they transferred me to Sumter County that gave me the info, but no site phone number, sorry.

Do as I did as a child;

Uh, YES and YES.

Or, do you really want to save a couple of dollars by doing that and then take your chances pouring into a valuable old car like that?

Stabile will not solve this problem. The problem is that this car, an 1986, has some steel parts in the gas tank and these do not like ethanol which becomes very corrosive to steel when water is absorbed. Stabil is very good for keeping the gasoline from breaking down, but does not prevent other damage. In any case I have solved the original problem.

Sumter County
 

From Solid Waste | Sumter County, FL - Official Website
I googled hazardous waste sumter county florida

Eligible Residential Drop-Off Items

Sumter County Solid Waste does provide a Citizen’s Drop-Off Area (CDA) at 819 CR 529, Lake Panasoffkee, FL 33538 for residents to drop off the following acceptable items for a fee (See Fee Schedule below):

Residential/Household Class 1 Waste/Garbage
Residential Recyclable Materials – No Charge
Plastics #1 through #7
Aluminum, Tin, and Steel Cans
Mixed Paper (Magazines, Newsprint, Office Paper,
Phone Books, Catalogs)
Clean Paper Bags
Waste Tires
Batteries, Car, rechargeable, normal household batteries
Scrap Metal
Cardboard
Brush, Construction, and Demolition Debris
Electronics
Furniture
Fire Extinguisher
Fees

Click here for a list of fees.

Paint Disposal Options

Paint cans are not accepted at the CDA.

If you have a large amount of paint, it is considered hazardous waste and we will only accept this item at one of the Mobile Collection days (see below).
If there is a small amount of latex paint left, open the paint lid and let the latex paint dry. Dried latex paint is not considered a hazardous waste and can be disposed with regular trash.
Small amounts of latex paint can also be mixed with kitty litter and allowed to dry with the lid off.
Empty paint cans should have the lid removed and can be disposed of with ordinary trash.


Fees effective 1/1/2021
Solid Waste Fees
Fee per Unit Unit
Household Waste Up to 35 Gallon Bag or Can $1.00 each
Over 35 Gallon Bag or Can $3.00 each
Tires Without rims $6.00 each
With rims $10.00 each
Furniture $5.00 cubic yard
Electronics
TV, Computer, Monitor, Printer, or Microwave $6.00 each
Brush and Debris Yard waste or construction and demolition debris $9.00 cubic yard
White Goods Refrigerator, air conditioner, washer, dryer, freezer, or oven/range $5.00 each

There is no fee for the disposal of recyclable items: batteries, scrap metal, gasoline, oil, oil filters, glass containers, plastic containers, cardboard containers, tin and aluminum cans.