Drop Cloths
There are three basic types of drop cloths used by painters for covering up during the painting process: canvas, fabric, paper and plastic. Drop cloths are intended to protect surfaces from paint spatter, they will stop (some better than others) paint spills also for a limited time (which may be only a few minutes for a canvas drop cloth) in which case you can roll or bundle up the soiled drop and place it into a plastic garbage bag to be dried out later. Leaving a drop will a heavy spill on top of a carpet etc... is asking for trouble, remove it and replace it with another. A drop cloth that receives a big spill will usually need to be cut into smaller drop cloths and the offending spill cut off.
Bleed through
While you should be OK with paint "spatters", paint "drips" can bleed through canvas and fabric drops cloths too, particularly if you walk on the drip whcih kind of pushes it through the canvas. While spatters should not be a problem, drips should be wiped off a canvas or
Canvas drop cloths
These are the most expensive but are washable and re-useable for many years. Canvas drops are usually used on the floor (except on wood floors where they may be slippery) because they are heavier and will stay in place better than either paper or plastic drops.
Fabric
For cost reasons, manufacturers have substituted other fabrics such as denim, for canvas in an effort to keep costs down. The denim drops are good in terms of absorbing and holding drips, but they are much stiffer than canvas and therefore not as easy to manipulate in the covering up process.