One day I was at my brothers house 80 miles away from mine,and as I was about to leave,he stood next to my van's drivers side window and we talked for a few minutes--a light drizzle was falling,and he stooped down to listen,said he heard something "squealing"...closer inspection revealed a galvanized deck screw with a phillips head was stuck in the tire tread,and the rain was bubbling up around it and making the squealing noise..
He said "Oh-Oh--you have a deck screw in your tire!--and I'm out of tire plugs,I just used the last one the other day"..--(He had a Snap-On tire plugging gun that took special plugs that look like rubber bullets)...he said "hold on a minute--let me make sure I don't have the other type you shove in left"..
He went in his garage,didn't find any..I usually carry some in my vehicles,along with a 12V compressor--but didn't have any tire plugs with me this trip,just the compressor..
My brother went back in his garage and returned with a phillips screwdriver,and a tube of black silicone RTV ,and he unscrewed the screw a bit,and put some RTV under the head of it,and tightened it back up until it was below flush with the tread..the leak stopped!..
I waited about 15 minutes before driving off,and prayed I'd make it home without getting a flat...not only did the van make it home,I parked it,and I used two other vehicles I had registered and road legal to get to work and cruise around in for the next few weeks--mostly my van only got used on longer trips when I'd go camping,or sleep over at a concert site,etc..
I completely forgot about the screw being in the tire--and I drove the van the next summer to Nashville TN,and all over New England,without any troubles..then one day I noticed some steel cords were showing on the edges of the left front tire,so I went and got another "good used" tire to put on the rim--when I dismounted it,I sliced my hand open on the screw,which was poking inside the tire,it was about 3" long--and I suddenly remembered that day at my brothers house!--"OH YEAH!"...:tango_face_surprise..
The head of the screw was paper thin,and ready to punch thru the tire!..
The inside of the tire had some severe scuffing going on,from the screw rubbing against the sidewall--if it hadn't gone bald then,I bet it would have popped in another 50 miles!..
Since that incident I now try to keep tire plugs with me,but I dont always have any..I keep a few screws with countersunk heads in my tool box and have used a few as tire plugs with RTV in a pinch,and its worked every time..
I had a screw in one of my tractors front tires for years,I put one in after I ran a board with nails sticking out over,and I wanted to finish mowing before it got dark..as long as it still held air,I never bothered to plug the tire or replace it...