I found this on https://www.gsa.gov/portal/content/113602 Removing Linoleum Adhesive From FloorsProcedure code:965001SSource:Ohj - Shirley Maxwell & James C. Massey, 9/30/92Division:FinishesSection:Resilient FlooringLast Modified:08/02/2016 REMOVING LINOLEUM ADHESIVE FROM FLOORS PART 1---GENERAL 1.01 SUMMARY This procedure includes guidance on removing the mastic adhesive left behind when linoleum flooring has been removed. Linoleum flooring was very popular from 1863 to 1974. It was used historically as an original floor treatment in some GSA buildings. Linoleum's chief ingredient was linseed oil, pressed from flax seed, which became a tough, elastic material when exposed to air. The process essentially consisted of mixing linseed oil and gum with ground cork or wood flour, and pressing it onto burlap or canvas. It was then glued down to concrete or wood floors using a mastic cement. See "General Project Guidelines" for general project guidelines to be used along with this procedureThese guidelines cover the following sections: Historic Structures Precautions Submittals Quality Assurance Delivery, Storage and Handling Project/Site Conditions Sequencing and Scheduling General Protection (Surface and Surrounding) These guidelines should be reviewed prior to performing this procedure and should be followed along with recommendations from the Regional Historic Preservation Officer (RHPO). PART 2---PRODUCTS 2.01 MATERIALS Clean, potable water Vinegar Citrus degreasing solvent such as "Limo Sol", or approved equal. Dry ice Chemical solvent such as isopropyl alcohol, paint thinner, xylol, lacquer thinner, or paint stripper. 2.02 EQUIPMENT Heat lamp or hot-air gun Putty knife or scraper PART 3---EXECUTION 3.01 ERECTION, INSTALLATION, APPLICATION NOTE: A waterproof glue is usually applied at the edges and seams of the linoleum; the center of the felt layers is usually attached with a water soluble paste. Soak the mastic area in hot water for 20-60 minutes or until soft.\ If this is not effective, try adding vinegar or high-strength citrus degreasing solvent to the water and then soak for 20-60 minutes until soft. If mastic still will not soften, try applying heat to the surface using a lamp or hot-air gun. -OR- Try freezing the mastic with dry ice to break the bond with the substrate. If no other methods are effective in softening the mastic, test a chemical solvent on the area. NOTE: Be sure to test in an inconspicuous area to determine appropriate chemicals and strengths before proceeding with cleaning. Scrape away the softened mastic using a putty knife or garden edger. END OF SECTION interesting................

I feel for you, Marjie. It sounds like you have a leak that you need to address. But with only one full bath in the house you cannot afford the time for the whole shower pan construction. I bought my house in February, and they started the construction right away. I am still waiting for a few final details to be done, not to mention the correction for the shower problem. But at least we had a basement to live in while it was going on (complete with full bath!). Btw, our tub downstairs is that all-in-one construction (fiberglass? acrylic?), which I know isn't the dream shower you were probably thinking of, but one could probably be installed in a day or two without any tile work since it goes up the walls. It has nifty ledges on it. I'm curious what our pros on here think of that type of solution. You could still have a beautiful tile floor which wouldn't have the same waterproofing concerns. I spent a lot of money of my master bath, and I love my design, but the aggravation has not been worth it. And there is still no consensus on what is wrong, or the proper fix. Oh, and another thing. I prefer my new $36 shower head in the basement to the $500 one in the master bath that is too hard for me to turn the settings for the jets because my hands are too small. It wasn't like I got to see it before he installed it. This one does everything my expensive one does except that it doesn't have the slide bar: http://www.amazon.com/gp/product/B00JV5HO3G?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00 Actually, it does more. You can run the rain shower head and the hand held at the same time.

I wouldn't dream of using gasoline! I'm worried enough about the fumes from adhesive remover -- which is why I was looking for something milder that could still do the job... I wonder why bleach would work, that makes no sense. I found out the hard way that cat urine would remove old adhesive -- when we removed the original linoleum from our 1941 kitchen, our elderly feline was quite upset by the construction and started using the exposed subfloor instead of the litter box. Every spot she went, the remaining old adhesive came up easily. However, there are distinct disadvantages to that method!!! Hmm, maybe I should try cleaning ammonia? but, again, fumes...

I wouldn't apply any chemicals to the glue, because as other people mentioned, it will just gum it up and might cause problems with the new floor down the road. I once had a similar problem in my kitchen, and I had somewhat good luck with renting an edger like this one, with 36 grit paper. The key with this machine is to move it around constantly or it will eat through the entire plywood subfloor in no time. If you go that route, get plenty of spare disks, because it will gum up pretty fast. And practice first on a piece of scrap plywood. Your only other option unfortunately is to replace the whole subfloor. Good luck!