|"Is cleaning them physically with alcohol is really necessary?"|
If you want to probably cure your problem, yes. I have found it often cures problems like yours. If you do it properly, it cannot hurt.
If you were not having any problems with this same ram perviously, it is extremely unlikely there is anything wrong with the ram modules.
"...all the warnings about frying my RAM slots is not to my liking"
It's not rocket science. You just have to be careful.
"REMOVE the power to your case"
Either unplug the cord to the power supply on the case, or turn off the power on whatever that cord is plugged into - e.g. a multiple outlet power bar.
"Remove the ram..."
Push down on the latches at the ends of the ram slot a module is in, to put then in their down position. That unlocks slight projections on the the latches from engaging into notches on the ends of the modules, and often lifts the module slightly out of the slot. Pull straight up on the module
".... and clean it's contacts with isopropyl or methyl alcohol, or if you don't have either of those a solution made with a tiny drop of dish detergent in water will do. Wipe off the contacts with a tissue to make sure they are dry. Don't touch the contacts with your fingers after that. Check the ram slots for mung - blow out or brush out (e.g. with a tiny artist's paintbrish)any you mung you see. Insert the ram making sure it is the right way and fully seated, latch the latches.
The notches in the contact edge on the ram modules MUST line up with the bumps in the ram slots..."
If you make sure the notches line up with the bumps in the slot, you can't do the ram or the mboard any harm. When you are inserting the ram, the latches at the ends of the slots should be in their down position. When you press down on the center of the ram module, the latches will be forced into their up position, auto align the module so that it goes to the bottom of the ram slot and lines up with the ram slot contacts properly, and the latches will lock into notches on the ends of the modules.
If you follow the above properly, you don't have to worry above any of the rest.....
"- if you install the module backwards, the latches will be difficult or impossible to latch on one end or both ends, and if you try to boot the computer with the module backwards, the module that is backwards will FRY instantly, the ram slot it is in will FRY instantly and vaporize some of the contacts in the slot and that slot can never be used again, even if you clean up the melted plastic, carbon, and any bridged contacts in that slot."
There are often similar directions and diagrams or pictures about how to install or remove your ram in the manual for your mboard, or certainly in the FAQs on the web site of the mboard maker, or in the FAQs on the web site of a brand name system builder if that applies to you, or in the FAQs on the web site of major ram module manufacturers or distributors.
If you are still leery about doing it, have someone who is competant do it for you.
Your problem will not be solved if you do nothing, and it will likely get worse.